How to get a time zone from a location using latitude and longitude coordinates?

Given the latitude and longitude of a location, how does one know what time zone is in effect in that location?

In most cases, we are looking for an IANA/Olson time zone id, although some services may return just a UTC offset, or some other time zone identifier. Please read the timezone tag info for details.

Time Zone Location Web Services

• Google Maps Time Zone API
• Bing Maps Time Zone API
• Azure Maps Time Zone API
• GeoNames Time Zone API
• TimeZoneDB API
• AskGeo - commercial (but arguably more accurate than GeoNames)
• GeoGarage Time Zone API - commercial, focusing on Nautical time zones.

Raw Time Zone Boundary Data

• Timezone Boundary Builder - builds time zone shapefiles from OpenStreetMaps map data. Includes territorial waters near coastlines.

The following projects have previously been sources of time zone boundary data, but are no longer actively maintained.

• tz_world - the original shapefile data from Eric Muller
• whereonearth-timezone - GeoJSON version with WOEDB data merged in

Time Zone Geolocation Offline Implementations

Implementations that use the Timezone Boundary Builder data

• node-geo-tz - JavaScript library (Node.js only)
• timespace - JavaScript library
• tz-lookup-oss - JavaScript library
• GeoTimeZone - .NET library
• Geo-Timezone - PHP library
• timezonefinder - Python library
• ZoneDetect - C library
• Timeshape - Java library
• TimeZoneMap - Java and Android library
• lutz - R library
• go-tz - Go library
• Timezone lookup - Go library
• docker-timezone-lookup - docker container wrapping node-geo-tz

Implementations that use the older tz_world data

• latlong - Go library (Read this post also.)
• TimeZoneMapper - Java library
• tzwhere - JavaScript/Node library
• pytzwhere - Python library
• timezone_finder - Ruby library
• LatLongToTimeZone - Java and Swift libraries
• What Time is it here? - Blog post describing PHP and MongoDB
• rundel/timezone - R library

Libraries that call one of the web services

• timezone - Ruby gem that calls GeoNames
• AskGeo has its own libraries for calling from Java or .Net
• GeoNames has client libraries for just about everything

Self-hosted web services

• geo2tz - based on Timezone lookup, available via Docker image

Other Ideas

• Find the nearest city with an R-Tree
• Find the nearest city with MySQL

Please update this list if you know of any others

Also, note that the nearest-city approach may not yield the "correct" result, just an approximation.

Conversion To Windows Zones

Most of the methods listed will return an IANA time zone id. If you need to convert to a Windows time zone for use with the TimeZoneInfo class in .NET, use the TimeZoneConverter library.

Don't use zone.tab

The tz database includes a file called zone.tab. This file is primarily used to present a list of time zones for a user to pick from. It includes the latitude and longitude coordinates for the point of reference for each time zone. This allows a map to be created highlighting these points. For example, see the interactive map shown on the moment-timezone home page.

While it may be tempting to use this data to resolve the time zone from a latitude and longitude coordinates, consider that these are points - not boundaries. The best one could do would be to determine the closest point, which in many cases will not be the correct point.

Consider the following example:

                           

The two squares represent different time zones, where the black dot in each square is the reference location, such as what can be found in zone.tab. The blue dot represents the location we are attempting to find a time zone for. Clearly, this location is within the orange zone on the left, but if we just look at closest distance to the reference point, it will resolve to the greenish zone on the right.

How about this solution for node.js https://github.com/mattbornski/tzwhere

And its Python counterpart: https://github.com/pegler/pytzwhere

We at Teleport just started opening up our API's and one of the usecases is also exposing TZ information for coordinates.

For example one could request all our available TZ information for coordinates in following manner:

curl -s https://api.teleport.org/api/locations/59.4372,24.7453/?embed=location:nearest-cities/location:nearest-city/city:timezone/tz:offsets-now | jq '._embedded."location:nearest-cities"[0]._embedded."location:nearest-city"._embedded."city:timezone"'

This would return the following

{
  "_embedded": {
    "tz:offsets-now": {
      "_links": {
        "self": {
          "href": "https://api.teleport.org/api/timezones/iana:Europe%2FTallinn/offsets/?date=2015-09-07T11%3A20%3A09Z"
        }
      },
      "base_offset_min": 120,
      "dst_offset_min": 60,
      "end_time": "2015-10-25T01:00:00Z",
      "short_name": "EEST",
      "total_offset_min": 180,
      "transition_time": "2015-03-29T01:00:00Z"
    }
  },
  "_links": {
    "self": {
      "href": "https://api.teleport.org/api/timezones/iana:Europe%2FTallinn/"
    },
    "tz:offsets": {
      "href": "https://api.teleport.org/api/timezones/iana:Europe%2FTallinn/offsets/{?date}",
      "templated": true
    },
    "tz:offsets-now": {
      "href": "https://api.teleport.org/api/timezones/iana:Europe%2FTallinn/offsets/?date=2015-09-07T11%3A20%3A09Z"
    }
  },
  "iana_name": "Europe/Tallinn"
}

For the example I used ./jq for JSON parsing.

Here's how you can use Google's script editor to get the timezoneName and timeZoneId inside a gsheet.

Step 1. Get an API key for Google's timezone API

Step 2. Create a new gsheet. Underneath the 'tools' menu click 'script editor'. Add the following code:

function getTimezone(lat, long) {  
  var apiKey = 'INSERTAPIKEYHERE'
  var url = 'https://maps.googleapis.com/maps/api/timezone/json?location=' + lat + ',' + long + '&timestamp=1331161200&key=' + apiKey 
  var response = UrlFetchApp.fetch(url);
  var data = JSON.parse(response.getContentText());
  return data["timeZoneName"];
}

Step 3. Save and publish your getTimezone() function and use it as shown in the image above.

You can use geolocator.js for easily getting timezone and more...

It uses Google APIs that require a key. So, first you configure geolocator:

geolocator.config({
    language: "en",
    google: {
        version: "3",
        key: "YOUR-GOOGLE-API-KEY"
    }
});

Get TimeZone if you have the coordinates:

geolocator.getTimeZone(options, function (err, timezone) {
    console.log(err || timezone);
});

Example output:

{
    id: "Europe/Paris",
    name: "Central European Standard Time",
    abbr: "CEST",
    dstOffset: 0,
    rawOffset: 3600,
    timestamp: 1455733120
}

Locate then get TimeZone and more

If you don't have the coordinates, you can locate the user position first.

Example below will first try HTML5 Geolocation API to get the coordinates. If it fails or rejected, it will get the coordinates via Geo-IP look-up. Finally, it will get the timezone and more...

var options = {
    enableHighAccuracy: true,
    timeout: 6000,
    maximumAge: 0,
    desiredAccuracy: 30,
    fallbackToIP: true, // if HTML5 fails or rejected
    addressLookup: true, // this will get full address information
    timezone: true,
    map: "my-map" // this will even create a map for you
};
geolocator.locate(options, function (err, location) {
    console.log(err || location);
});

Example output:

{
    coords: {
        latitude: 37.4224764,
        longitude: -122.0842499,
        accuracy: 30,
        altitude: null,
        altitudeAccuracy: null,
        heading: null,
        speed: null
    },
    address: {
        commonName: "",
        street: "Amphitheatre Pkwy",
        route: "Amphitheatre Pkwy",
        streetNumber: "1600",
        neighborhood: "",
        town: "",
        city: "Mountain View",
        region: "Santa Clara County",
        state: "California",
        stateCode: "CA",
        postalCode: "94043",
        country: "United States",
        countryCode: "US"
    },
    formattedAddress: "1600 Amphitheatre Parkway, Mountain View, CA 94043, USA",
    type: "ROOFTOP",
    placeId: "ChIJ2eUgeAK6j4ARbn5u_wAGqWA",
    timezone: {
        id: "America/Los_Angeles",
        name: "Pacific Standard Time",
        abbr: "PST",
        dstOffset: 0,
        rawOffset: -28800
    },
    flag: "//cdnjs.cloudflare.com/ajax/libs/flag-icon-css/2.3.1/flags/4x3/us.svg",
    map: {
        element: HTMLElement,
        instance: Object, // google.maps.Map
        marker: Object, // google.maps.Marker
        infoWindow: Object, // google.maps.InfoWindow
        options: Object // map options
    },
    timestamp: 1456795956380
}

https://en.wikipedia.org/wiki/Great-circle_distance

And here is a good implementation using JSON data: https://github.com/agap/llttz

public TimeZone nearestTimeZone(Location node) {
    double bestDistance = Double.MAX_VALUE;
    Location bestGuess = timeZones.get(0);

    for (Location current : timeZones.subList(1, timeZones.size())) {
        double newDistance = distanceInKilometers(node, current);

        if (newDistance < bestDistance) {
            bestDistance = newDistance;
            bestGuess = current;
        }
    }

    return java.util.TimeZone.getTimeZone(bestGuess.getZone());
}

  protected double distanceInKilometers(final double latFrom, final double lonFrom, final double latTo, final double lonTo) {
        final double meridianLength = 111.1;
        return meridianLength * centralAngle(latFrom, lonFrom, latTo, lonTo);
    }

    protected double centralAngle(final Location from, final Location to) {
        return centralAngle(from.getLatitude(), from.getLongitude(), to.getLatitude(), to.getLongitude());
    }

    protected double centralAngle(final double latFrom, final double lonFrom, final double latTo, final double lonTo) {
        final double latFromRad = toRadians(latFrom),
                lonFromRad = toRadians(lonFrom),
                latToRad   = toRadians(latTo),
                lonToRad   = toRadians(lonTo);

        final double centralAngle = toDegrees(acos(sin(latFromRad) * sin(latToRad) + cos(latFromRad) * cos(latToRad) * cos(lonToRad - lonFromRad)));

        return centralAngle <= 180.0 ? centralAngle : (360.0 - centralAngle);
    }

    protected double distanceInKilometers(final Location from, final Location to) {
        return distanceInKilometers(from.getLatitude(), from.getLongitude(), to.getLatitude(), to.getLongitude());
    }
}

1. There are several sources online that have geojson data for timezones (here's one, here's another)

2. Use a geometry library to create polygon objects from the geojson coordinates (shapely [python], GEOS [c++], JTS [java], NTS [.net]).

3. Convert your lat/lng to a point object (however your library represents that) and check if it intersects the timezone polygon.

   from shapely.geometry import Polygon, Point
   
   def get_tz_from_lat_lng(lat, lng):
       for tz, geojson in timezones.iteritems():
           coordinates = geojson['features'][0]['geometry']['coordinates']
           polygon = Polygon(coordinates)
           point = Point(lng, lat)
           if polygon.contains(point):
               return tz
   

It's indeed important to recognize that this a more complicated problem than most would suspect. In practice many of us are also willing to accept a working set of code that works for "as many cases as possible", where at least its fatal issues can be identified and minimized collectively. So I post this with all of that and the spirit of the OP in mind. Finally, for practical value to others who are trying to convert GPS to timezone with the end goal of having a location-sensitive time object (and more importantly to help advance the quality of average implementations with time objects that follow from this wiki) here is what I generated in Python (please feel free to edit):

import pytz
from datetime import datetime
from tzwhere import tzwhere

def timezoned_unixtime(latitude, longitude, dt):
    tzw = tzwhere.tzwhere()
    timezone_str = tzw.tzNameAt(latitude, longitude)
    timezone = pytz.timezone(timezone_str)
    timezone_aware_datetime = timezone.localize(dt, is_dst=None)
    unix_time = (timezone_aware_datetime - datetime(1970, 1, 1, tzinfo=pytz.utc)).total_seconds()
    return unix_time

dt = datetime(year=2017, month=1, day=17, hour=12, minute=0, second=0)
print timezoned_unixtime(latitude=40.747854, longitude=-74.004733, dt=dt)

disclosure: I am the author of the docker-image described below

I have wrapped https://github.com/evansiroky/node-geo-tz in a very simple docker-container

> https://hub.docker.com/repository/docker/tobias74/timezone-lookup

You can start the docker-container with

docker run -p 80:3000 tobias74/timezone-lookup:latest

This exposes the lookup-service on your localhost on port 3000. You can then do a timezone-lookup by

curl "localhost:3000/timezone?latitude=12&longitude=34"

Try this code for use Google Time Zone API from Java with current NTP Time Client and correct UTC_Datetime_from_timestamp convert:

String get_xml_server_reponse(String server_url){
	 
    URL xml_server = null;
    
    String xmltext = "";
 	
 	InputStream input;


	try {
		xml_server = new URL(server_url);

	
		try {
			input = xml_server.openConnection().getInputStream();
		
		 
		    final BufferedReader reader = new BufferedReader(new InputStreamReader(input));
	        final StringBuilder sBuf = new StringBuilder();

	        String line = null;
	        try {
	            while ((line = reader.readLine()) != null) 
	            {
	                sBuf.append(line);
	            }
	           } 
	        catch (IOException e) 
	          {
	                Log.e(e.getMessage(), "XML parser, stream2string 1");
	          } 
	        finally {
	            try {
	                input.close();
	                }
	            catch (IOException e) 
	            {
	                Log.e(e.getMessage(), "XML parser, stream2string 2");
	            }
	        }
	        
	        xmltext =  sBuf.toString();
	        
		} catch (IOException e1) {

				e1.printStackTrace();
			}
        
        
		} catch (MalformedURLException e1) {

		  e1.printStackTrace();
		}

	 return  xmltext;
   
  }     


 private String get_UTC_Datetime_from_timestamp(long timeStamp){

	try{
		
		Calendar cal = Calendar.getInstance();
  		TimeZone tz = cal.getTimeZone();
  		
  		int tzt = tz.getOffset(System.currentTimeMillis());
  			  			  		
  		timeStamp -= tzt;
		
	    // DateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss",Locale.getDefault());
	    DateFormat sdf = new SimpleDateFormat();
	    Date netDate = (new Date(timeStamp));
	    return sdf.format(netDate);
	}
	catch(Exception ex){
	    return "";
	 }
	} 
 
 class NTP_UTC_Time
 {
     private static final String TAG = "SntpClient";

     private static final int RECEIVE_TIME_OFFSET = 32;
     private static final int TRANSMIT_TIME_OFFSET = 40;
     private static final int NTP_PACKET_SIZE = 48;

     private static final int NTP_PORT = 123;
     private static final int NTP_MODE_CLIENT = 3;
     private static final int NTP_VERSION = 3;

     // Number of seconds between Jan 1, 1900 and Jan 1, 1970
     // 70 years plus 17 leap days
     private static final long OFFSET_1900_TO_1970 = ((365L * 70L) + 17L) * 24L * 60L * 60L;

     private long mNtpTime;

     public boolean requestTime(String host, int timeout) {
         try {
             DatagramSocket socket = new DatagramSocket();
             socket.setSoTimeout(timeout);
             InetAddress address = InetAddress.getByName(host);
             byte[] buffer = new byte[NTP_PACKET_SIZE];
             DatagramPacket request = new DatagramPacket(buffer, buffer.length, address, NTP_PORT);

             buffer[0] = NTP_MODE_CLIENT | (NTP_VERSION << 3);

             writeTimeStamp(buffer, TRANSMIT_TIME_OFFSET);

             socket.send(request);

             // read the response
             DatagramPacket response = new DatagramPacket(buffer, buffer.length);
             socket.receive(response);          
             socket.close();

             mNtpTime = readTimeStamp(buffer, RECEIVE_TIME_OFFSET);            
         } catch (Exception e) {
           //  if (Config.LOGD) Log.d(TAG, "request time failed: " + e);
             return false;
         }

         return true;
     }


     public long getNtpTime() {
         return mNtpTime;
     }


     /**
      * Reads an unsigned 32 bit big endian number from the given offset in the buffer.
      */
     private long read32(byte[] buffer, int offset) {
         byte b0 = buffer[offset];
         byte b1 = buffer[offset+1];
         byte b2 = buffer[offset+2];
         byte b3 = buffer[offset+3];

         // convert signed bytes to unsigned values
         int i0 = ((b0 & 0x80) == 0x80 ? (b0 & 0x7F) + 0x80 : b0);
         int i1 = ((b1 & 0x80) == 0x80 ? (b1 & 0x7F) + 0x80 : b1);
         int i2 = ((b2 & 0x80) == 0x80 ? (b2 & 0x7F) + 0x80 : b2);
         int i3 = ((b3 & 0x80) == 0x80 ? (b3 & 0x7F) + 0x80 : b3);

         return ((long)i0 << 24) + ((long)i1 << 16) + ((long)i2 << 8) + (long)i3;
     }

     /**
      * Reads the NTP time stamp at the given offset in the buffer and returns 
      * it as a system time (milliseconds since January 1, 1970).
      */    
     private long readTimeStamp(byte[] buffer, int offset) {
         long seconds = read32(buffer, offset);
         long fraction = read32(buffer, offset + 4);
         return ((seconds - OFFSET_1900_TO_1970) * 1000) + ((fraction * 1000L) / 0x100000000L);        
     }

     /**
      * Writes 0 as NTP starttime stamp in the buffer. --> Then NTP returns Time OFFSET since 1900
      */    
     private void writeTimeStamp(byte[] buffer, int offset) {        
         int ofs =  offset++;

         for (int i=ofs;i<(ofs+8);i++)
           buffer[i] = (byte)(0);             
     }

 }
           
 String get_time_zone_time(GeoPoint gp){
	       	
    	String erg = "";
    	String raw_offset = "";
        String dst_offset = "";
   
    	double Longitude = gp.getLongitudeE6()/1E6;
		double Latitude = gp.getLatitudeE6()/1E6;
    		  	    	
    				
		
		long tsLong = 0; // System.currentTimeMillis()/1000;
 
        NTP_UTC_Time client = new NTP_UTC_Time();

        if (client.requestTime("pool.ntp.org", 2000)) {              
          tsLong = client.getNtpTime();
        }
		
		if (tsLong != 0)
		{
			
		tsLong = tsLong  / 1000;
															
		// https://maps.googleapis.com/maps/api/timezone/xml?location=39.6034810,-119.6822510&timestamp=1331161200&sensor=false
		
    	String request = "https://maps.googleapis.com/maps/api/timezone/xml?location="+Latitude+","+ Longitude+ "&timestamp="+tsLong +"&sensor=false";
    	 	     	    
    	String xmltext = get_xml_server_reponse(request);
    	
  		if(xmltext.compareTo("")!= 0)
  		{
    	
		 int startpos = xmltext.indexOf("<TimeZoneResponse");
         xmltext = xmltext.substring(startpos);
 	         
 	      		 	           		 	         
 	    
        XmlPullParser parser;
		try {
			parser = XmlPullParserFactory.newInstance().newPullParser();
		

	         parser.setInput(new StringReader (xmltext));
	  
	         int eventType = parser.getEventType();  
	         
	         String tagName = "";
	        
	         
	         while(eventType != XmlPullParser.END_DOCUMENT) {
	             switch(eventType) {
	               	                     	   	           
	                 case XmlPullParser.START_TAG:
	   
	                       tagName = parser.getName();
	                       	                     	                          	           	                     	                     	                        
	                     break;
	                       	                          	                   	                          	                          	                    	       	          
	    	         
	                 case XmlPullParser.TEXT :
	    	        	
	                 	
	                 	if  (tagName.equalsIgnoreCase("raw_offset"))
	                 	  if(raw_offset.compareTo("")== 0)		            	  		 
	                 	    raw_offset = parser.getText();  
	                 	
	                 	if  (tagName.equalsIgnoreCase("dst_offset"))
	                 	  if(dst_offset.compareTo("")== 0)
	                 		dst_offset = parser.getText();  
	    	        		
	                 	
	    	        	break;   
	                     
	             }
	
	             try {
						eventType = parser.next();
					} catch (IOException e) {
			
						e.printStackTrace();
					}
	         
				}
	         
				} catch (XmlPullParserException e) {
				
					e.printStackTrace();
					erg += e.toString();
				}
		
  		}	   
  		
  		int ro = 0;
  		if(raw_offset.compareTo("")!= 0)
  		{ 
  			float rof = str_to_float(raw_offset);
  			ro = (int)rof;
  		}
  		
  		int dof = 0;
  		if(dst_offset.compareTo("")!= 0)
  		{ 
  			float doff = str_to_float(dst_offset);
  			dof = (int)doff;
  		}
  		
  	    tsLong = (tsLong + ro + dof) * 1000;
  		
  		
  		
  		erg = get_UTC_Datetime_from_timestamp(tsLong);
		}
  		
    
  return erg;
 
}

And use it with:

GeoPoint gp = new GeoPoint(39.6034810,-119.6822510);
String Current_TimeZone_Time = get_time_zone_time(gp);

Ok here is the short Version without correct NTP Time:

String get_xml_server_reponse(String server_url){

URL xml_server = null;

String xmltext = "";

InputStream input;


try {
    xml_server = new URL(server_url);


    try {
        input = xml_server.openConnection().getInputStream();


        final BufferedReader reader = new BufferedReader(new InputStreamReader(input));
        final StringBuilder sBuf = new StringBuilder();

        String line = null;
        try {
            while ((line = reader.readLine()) != null) 
            {
                sBuf.append(line);
            }
           } 
        catch (IOException e) 
          {
                Log.e(e.getMessage(), "XML parser, stream2string 1");
          } 
        finally {
            try {
                input.close();
                }
            catch (IOException e) 
            {
                Log.e(e.getMessage(), "XML parser, stream2string 2");
            }
        }

        xmltext =  sBuf.toString();

    } catch (IOException e1) {

            e1.printStackTrace();
        }


    } catch (MalformedURLException e1) {

      e1.printStackTrace();
    }

 return  xmltext;

} 


long get_time_zone_time_l(GeoPoint gp){
	       	
    
    	String raw_offset = "";
        String dst_offset = "";
   
    	double Longitude = gp.getLongitudeE6()/1E6;
		double Latitude = gp.getLatitudeE6()/1E6;
						
		long tsLong = System.currentTimeMillis()/1000;
 
     			
		if (tsLong != 0)
		{
																						
		// https://maps.googleapis.com/maps/api/timezone/xml?location=39.6034810,-119.6822510&timestamp=1331161200&sensor=false
		
    	String request = "https://maps.googleapis.com/maps/api/timezone/xml?location="+Latitude+","+ Longitude+ "&timestamp="+tsLong +"&sensor=false";
    	 	     	    
    	String xmltext = get_xml_server_reponse(request);
    	
  		if(xmltext.compareTo("")!= 0)
  		{
    	
		 int startpos = xmltext.indexOf("<TimeZoneResponse");
         xmltext = xmltext.substring(startpos);
 	         
 	      		 	           		 	         
 	    
        XmlPullParser parser;
		try {
			parser = XmlPullParserFactory.newInstance().newPullParser();
		

	         parser.setInput(new StringReader (xmltext));
	  
	         int eventType = parser.getEventType();  
	         
	         String tagName = "";
	        
	         
	         while(eventType != XmlPullParser.END_DOCUMENT) {
	             switch(eventType) {
	               	                     	   	           
	                 case XmlPullParser.START_TAG:
	   
	                       tagName = parser.getName();
	                       	                     	                          	           	                     	                     	                        
	                     break;
	                       	                          	                   	                          	                          	                    	       	          
	    	         
	                 case XmlPullParser.TEXT :
	    	        	
	                 	
	                 	if  (tagName.equalsIgnoreCase("raw_offset"))
	                 	  if(raw_offset.compareTo("")== 0)		            	  		 
	                 	    raw_offset = parser.getText();  
	                 	
	                 	if  (tagName.equalsIgnoreCase("dst_offset"))
	                 	  if(dst_offset.compareTo("")== 0)
	                 		dst_offset = parser.getText();  
	    	        		
	                 	
	    	        	break;   
	                     
	             }
	
	             try {
						eventType = parser.next();
					} catch (IOException e) {
			
						e.printStackTrace();
					}
	         
				}
	         
				} catch (XmlPullParserException e) {
				
					e.printStackTrace();
					erg += e.toString();
				}
		
  		}	   
  		
  		int ro = 0;
  		if(raw_offset.compareTo("")!= 0)
  		{ 
  			float rof = str_to_float(raw_offset);
  			ro = (int)rof;
  		}
  		
  		int dof = 0;
  		if(dst_offset.compareTo("")!= 0)
  		{ 
  			float doff = str_to_float(dst_offset);
  			dof = (int)doff;
  		}
  		
  	    tsLong = (tsLong + ro + dof) * 1000;
  		
  	
		}
  		
    
  return tsLong;
 
}

And use it with:

GeoPoint gp = new GeoPoint(39.6034810,-119.6822510);
long Current_TimeZone_Time_l = get_time_zone_time_l(gp);

If you want to use geonames.org then use this code. (But geonames.org is very slow sometimes)

String get_time_zone_time_geonames(GeoPoint gp){
	 
	
    	String erg = "";
   
    	double Longitude = gp.getLongitudeE6()/1E6;
		double Latitude = gp.getLatitudeE6()/1E6;
    	
  
    	
    	String request = "http://ws.geonames.org/timezone?lat="+Latitude+"&lng="+ Longitude+ "&style=full";
    	 	     	    	
    	URL time_zone_time = null;
    	
    	InputStream input;
  	   // final StringBuilder sBuf = new StringBuilder();
  	 

		try {
			time_zone_time = new URL(request);
	
		
		try {
			input = time_zone_time.openConnection().getInputStream();
		
		 
		final BufferedReader reader = new BufferedReader(new InputStreamReader(input));
	        final StringBuilder sBuf = new StringBuilder();

	        String line = null;
	        try {
	            while ((line = reader.readLine()) != null) {
	                sBuf.append(line);
	            }
	        } catch (IOException e) {
	                Log.e(e.getMessage(), "XML parser, stream2string 1");
	        } finally {
	            try {
	                input.close();
	            } catch (IOException e) {
	                Log.e(e.getMessage(), "XML parser, stream2string 2");
	            }
	        }
	
	        
		  					  			  					  					
			
			 String xmltext = sBuf.toString();
 	        
			
			 int startpos = xmltext.indexOf("<geonames");
 	         xmltext = xmltext.substring(startpos);
	 	         
	 	      		 	           		 	         
	 	    
 	        XmlPullParser parser;
			try {
				parser = XmlPullParserFactory.newInstance().newPullParser();
			
    
            parser.setInput(new StringReader (xmltext));
     
            int eventType = parser.getEventType();  
            
            String tagName = "";
            
            while(eventType != XmlPullParser.END_DOCUMENT) {
                switch(eventType) {
                  	                     	   	           
                    case XmlPullParser.START_TAG:
      
                          tagName = parser.getName();
                          	                     	                          	           	                     	                     	                        
                        break;
                          	                          	                   	                          	                          	                    	       	          
       	         
                    case XmlPullParser.TEXT :
       	        	
                    	
                    	if  (tagName.equalsIgnoreCase("time"))
                    	  erg = parser.getText();  
       	        		
                    	
       	        	break;   
                        
                }
   
                try {
					eventType = parser.next();
				} catch (IOException e) {
		
					e.printStackTrace();
				}
            
			}
            
			} catch (XmlPullParserException e) {
			
				e.printStackTrace();
				erg += e.toString();
			}
	 	         
	 	       	                		 	           		 	           		 	           		 	           		 	           		 	           		 	           		 	           		 	           		 	           		 	           		 	         
	 	         
			} catch (IOException e1) {

				e1.printStackTrace();
			}
	 	         
	 	         
			} catch (MalformedURLException e1) {

				e1.printStackTrace();
			}
    	
    	
		    
    	
		    
        return erg;
	 
 }

And use it with:

GeoPoint gp = new GeoPoint(39.6034810,-119.6822510);
String Current_TimeZone_Time = get_time_zone_time_geonames(gp);

by using latitude and longitude get time zone of current location below code worked for me

String data = null;			
LocationManager locationManager = (LocationManager) getSystemService(LOCATION_SERVICE);
Location ll = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
double lat = 0,lng = 0;
if(ll!=null){
    lat=ll.getLatitude();
    lng=ll.getLongitude();
}
System.out.println(" Last known location of device  == "+lat+"    "+lng);
			
InputStream iStream = null; 
HttpURLConnection urlConnection = null;
try{
    timezoneurl = timezoneurl+"location=22.7260783,75.8781553&timestamp=1331161200";   			    	
    // timezoneurl = timezoneurl+"location="+lat+","+lng+"&timestamp=1331161200";
		    	    
    URL url = new URL(timezoneurl);                
    // Creating an http connection to communicate with url 
    urlConnection = (HttpURLConnection) url.openConnection(); 
           
    // Connecting to url 
    urlConnection.connect();                

    // Reading data from url 
    iStream = urlConnection.getInputStream();

    BufferedReader br = new BufferedReader(new InputStreamReader(iStream));

    StringBuffer sb  = new StringBuffer();
    String line = "";
    while( ( line = br.readLine())  != null){
        sb.append(line);
	}
    data = sb.toString();
    br.close();

}catch(Exception e){
    Log.d("Exception while downloading url", e.toString());
}finally{
    try {
        iStream.close();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
    urlConnection.disconnect();
}

try {
    if(data!=null){
        JSONObject jobj=new JSONObject(data);
        timezoneId = jobj.getString("timeZoneId");
				
        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd hh:mm:ss");
        format.setTimeZone(TimeZone.getTimeZone(timezoneId));
				
        Calendar cl = Calendar.getInstance(TimeZone.getTimeZone(timezoneId));
        System.out.println("time zone id in android ==  "+timezoneId);
				
        System.out.println("time zone of  device in android == "+TimeZone.getTimeZone(timezoneId));
        System.out.println("time fo device in android "+cl.getTime());
    }
} catch (Exception e) {
    // TODO Auto-generated catch block
    e.printStackTrace();
}

From Guppy:

import geocoders
g = geocoders.GoogleV3()
place, (lat, lng) = g.geocode('Fairbanks')
print place, (lat, lng)
Fairbanks, AK, USA (64.8377778, -147.7163889)
timezone = g.timezone((lat, lng))
print timezone.dst

Bound method America/Anchorage.dst of DstTzInfo

America/Anchorage' LMT-1 day, 14:00:00 STD

For those of us using Javascript and looking to get a timezone from a zip code via Google APIs, here is one method.

1. Fetch the lat/lng via geolocation
2. fetch the timezone by pass that into the timezone API.

• Using Luxon here for timezone conversion.

Note: my understanding is that zipcodes are not unique across countries, so this is likely best suited for use in the USA.

const googleMapsClient; // instantiate your client here
const zipcode = '90210'
const myDateThatNeedsTZAdjustment; // define your date that needs adjusting
// fetch lat/lng from google api by zipcode
const geocodeResponse = await googleMapsClient.geocode({ address: zipcode }).asPromise();
if (geocodeResponse.json.status === 'OK') {
  lat = geocodeResponse.json.results[0].geometry.location.lat;
  lng = geocodeResponse.json.results[0].geometry.location.lng;
} else {
  console.log('Geocode was not successful for the following reason: ' + status);
}

// prepare lat/lng and timestamp of profile created_at to fetch time zone
const location = `${lat},${lng}`;
const timestamp = new Date().valueOf() / 1000;
const timezoneResponse = await googleMapsClient
  .timezone({ location: location, timestamp: timestamp })
  .asPromise();

const timeZoneId = timezoneResponse.json.timeZoneId;
// adjust by setting timezone
const timezoneAdjustedDate = DateTime.fromJSDate(
  myDateThatNeedsTZAdjustment
).setZone(timeZoneId);

If you prefer to avoid a web service, you can retrieve that information from the browser like this:

var d = new Date();
var usertime = d.toLocaleString();

//some browsers / OSs provide the timezone name in their local string
var tzsregex = /\b(ACDT|ACST|ACT|ADT|AEDT|AEST|AFT|AKDT|AKST|AMST|AMT|ART|AST|AWDT|AWST|AZOST|AZT|BDT|BIOT|BIT|BOT|BRT|BST|BTT|CAT|CCT|CDT|CEDT|CEST|CET|CHADT|CHAST|CIST|CKT|CLST|CLT|COST|COT|CST|CT|CVT|CXT|CHST|DFT|EAST|EAT|ECT|EDT|EEDT|EEST|EET|EST|FJT|FKST|FKT|GALT|GET|GFT|GILT|GIT|GMT|GST|GYT|HADT|HAEC|HAST|HKT|HMT|HST|ICT|IDT|IRKT|IRST|IST|JST|KRAT|KST|LHST|LINT|MART|MAGT|MDT|MET|MEST|MIT|MSD|MSK|MST|MUT|MYT|NDT|NFT|NPT|NST|NT|NZDT|NZST|OMST|PDT|PETT|PHOT|PKT|PST|RET|SAMT|SAST|SBT|SCT|SGT|SLT|SST|TAHT|THA|UYST|UYT|VET|VLAT|WAT|WEDT|WEST|WET|WST|YAKT|YEKT)\b/gi;

//in other browsers the timezone needs to be estimated based on the offset
var timezonenames = {"UTC+0":"GMT","UTC+1":"CET","UTC+2":"EET","UTC+3":"EEDT","UTC+3.5":"IRST","UTC+4":"MSD","UTC+4.5":"AFT","UTC+5":"PKT","UTC+5.5":"IST","UTC+6":"BST","UTC+6.5":"MST","UTC+7":"THA","UTC+8":"AWST","UTC+9":"AWDT","UTC+9.5":"ACST","UTC+10":"AEST","UTC+10.5":"ACDT","UTC+11":"AEDT","UTC+11.5":"NFT","UTC+12":"NZST","UTC-1":"AZOST","UTC-2":"GST","UTC-3":"BRT","UTC-3.5":"NST","UTC-4":"CLT","UTC-4.5":"VET","UTC-5":"EST","UTC-6":"CST","UTC-7":"MST","UTC-8":"PST","UTC-9":"AKST","UTC-9.5":"MIT","UTC-10":"HST","UTC-11":"SST","UTC-12":"BIT"};

var timezone = usertime.match(tzsregex);
if (timezone) {
    timezone = timezone[timezone.length-1];
} else {
    var offset = -1*d.getTimezoneOffset()/60;
    offset = "UTC" + (offset >= 0 ? "+" + offset : offset);
    timezone = timezonenames[offset];
}

//there are 3 variables can use to see the timezone
// usertime - full date
// offset - UTC offset time
// timezone - country

console.log('Full Date: ' + usertime);
console.log('UTC Offset: ' + offset);
console.log('Country Code Timezone: ' + timezone);

In my current case it is printing:

Full Date: ‎27‎/‎01‎/‎2014‎ ‎16‎:‎53‎:‎37 UTC Offset: UTC-3 Country Code Timezone: BRT

Hope it can be helpful.

  function jsonpRequest(url, data)
{
    let params = "";
    for (let key in data)
    {
        if (data.hasOwnProperty(key))
        {
            if (params.length == 0)
            {
                params += "?";
            }
            else
            {
                params += "&";
            }
            let encodedKey = encodeURIComponent(key);
            let encodedValue = encodeURIComponent(data[key]);
            params += encodedKey + "=" + encodedValue;
         }
    }
    let script = document.createElement('script');
    script.src = url + params;
    document.body.appendChild(script);
}

function getLocation() {
  if (navigator.geolocation) {
    navigator.geolocation.getCurrentPosition(showPosition);
  } else {
    x.innerHTML = "Geolocation is not supported by this browser.";
  }
}
let lat_ini=[]; let lon_ini=[];
function showPosition(position) {
  lat_ini= position.coords.latitude;
  lon_ini= position.coords.longitude;
}
////delay time between lines
function sleep(ms) {
  return new Promise(resolve => setTimeout(resolve, ms));
}
///////
function getGMT()
{
  getfinalGMT()
  getLocation()
  async function sample() {
    await sleep(2000);
let lat_str=lat_ini.toString();
let lng_str=" "+lon_ini.toString();

  let url = "https://api.opencagedata.com/geocode/v1/json";
  let data = {
    callback: "displayGMT",
    q: lat_str + lng_str,
    key: "fac4471073a347019196c1291e6a97d7"
  }
  jsonpRequest(url, data)
}
 sample();
 }
let your_GMT=[];
function displayGMT(data)
{
your_GMT=(Number(data.results[0].annotations.timezone.offset_string))
console.log(your_GMT)
}
/////
function getfinalGMT()
{
let lat=document.getElementById("lat_id").value; let lng=document.getElementById("lng_id").value;
let lat_str=lat.toString();
let lng_str=" "+lng.toString();

  let url = "https://api.opencagedata.com/geocode/v1/json";
  let data = {
    callback: "displayfinalGMT",
    q: lat + lng_str,
    key: "fac4471073a347019196c1291e6a97d7"
  }
  jsonpRequest(url, data)
 }
let final_GMT=[];
function displayfinalGMT(data)
{
final_GMT=(Number(data.results[0].annotations.timezone.offset_string))
console.log(final_GMT)
}
/////clock


const hourHand = document.querySelector('[data-hour-hand]')
const minuteHand = document.querySelector('[data-minute-hand]')
const secondHand = document.querySelector('[data-second-hand]')
  let dif_overall=[];
function setClock() {
   let gmt_diff=Number(your_GMT-final_GMT)/100
   if (gmt_diff>12){
      dif_overall=gmt_diff-12
   }
   else{
     dif_overall=gmt_diff
   }
    console.log(dif_overall)
  const currentDate = new Date()
  const secondsRatio = currentDate.getSeconds() / 60
  const minutesRatio = (secondsRatio + currentDate.getMinutes()) / 60
  const hoursRatio = (minutesRatio + currentDate.getHours() - dif_overall ) / 12
  setRotation(secondHand, secondsRatio)
  setRotation(minuteHand, minutesRatio)
  setRotation(hourHand, hoursRatio)
}

function setRotation(element, rotationRatio) {
  element.style.setProperty('--rotation', rotationRatio * 360)
}
function activate_clock(){
setClock()
setInterval(setClock, 1000)
}

*, *::after, *::before {
  box-sizing: border-box;
}

body {
  background: linear-gradient(to right, hsl(200, 100%, 50%), hsl(175, 100%, 50%));
  display: flex;
  justify-content: center;
  align-items: center;
  min-height: 100vh;
  overflow: hidden;
}

.clock {
  width: 200px;
  height: 200px;
  background-color: rgba(255, 255, 255, .8);
  border-radius: 50%;
  border: 2px solid black;
  position: relative;
}

.clock .number {
  --rotation: 0;
  position: absolute;
  width: 100%;
  height: 100%;
  text-align: center;
  transform: rotate(var(--rotation));
  font-size: 1.5rem;
}

.clock .number1 { --rotation: 30deg; }
.clock .number2 { --rotation: 60deg; }
.clock .number3 { --rotation: 90deg; }
.clock .number4 { --rotation: 120deg; }
.clock .number5 { --rotation: 150deg; }
.clock .number6 { --rotation: 180deg; }
.clock .number7 { --rotation: 210deg; }
.clock .number8 { --rotation: 240deg; }
.clock .number9 { --rotation: 270deg; }
.clock .number10 { --rotation: 300deg; }
.clock .number11 { --rotation: 330deg; }

.clock .hand {
  --rotation: 0;
  position: absolute;
  bottom: 50%;
  left: 50%;
  border: 1px solid white;
  border-top-left-radius: 10px;
  border-top-right-radius: 10px;
  transform-origin: bottom;
  z-index: 10;
  transform: translateX(-50%) rotate(calc(var(--rotation) * 1deg));
}

.clock::after {
  content: '';
  position: absolute;
  background-color: black;
  z-index: 11;
  width: 15px;
  height: 15px;
  top: 50%;
  left: 50%;
  transform: translate(-50%, -50%);
  border-radius: 50%;
}

.clock .hand.second {
  width: 3px;
  height: 45%;
  background-color: red;
}

.clock .hand.minute {
  width: 7px;
  height: 40%;
  background-color: black;
}

.clock .hand.hour {
  width: 10px;
  height: 35%;
  background-color: black;
}














/* Background Styles Only */

@import url('https://fonts.googleapis.com/css?family=Raleway');

* {
    font-family: Raleway;
}

.side-links {
  position: absolute;
  top: 15px;
  right: 15px;
}

.side-link {
  display: flex;
  align-items: center;
  justify-content: center;
  text-decoration: none;
  margin-bottom: 10px;
  color: white;
  width: 180px;
  padding: 10px 0;
  border-radius: 10px;
}

.side-link-youtube {
  background-color: red;
}

.side-link-twitter {
  background-color: #1DA1F2;
}

.side-link-github {
  background-color: #6e5494;
}

.side-link-text {
  margin-left: 10px;
  font-size: 18px;
}

.side-link-icon {
  color: white;
  font-size: 30px;
}

   <input type="text" id="lat_id" placeholder="lat"><br><br>
  <input type="text" id="lng_id" placeholder="lng"><br><br>
<button class="text" onClick="getLocation()">Location</button>
<button class="text" onClick="getGMT()"> GMT</button>
<button class="text" onClick="activate_clock()"> Activate</button>
<div class="clock">
  <div class="hand hour" data-hour-hand></div>
  <div class="hand minute" data-minute-hand></div>
  <div class="hand second" data-second-hand></div>
  <div class="number number1">1</div>
  <div class="number number2">2</div>
  <div class="number number3">3</div>
  <div class="number number4">4</div>
  <div class="number number5">5</div>
  <div class="number number6">6</div>
  <div class="number number7">7</div>
  <div class="number number8">8</div>
  <div class="number number9">9</div>
  <div class="number number10">10</div>
  <div class="number number11">11</div>
  <div class="number number12">12</div>
</div>