Detect timezone abbreviation using JavaScript

I need a way to detect the timezone of a given date object. I do NOT want the offset, nor do I want the full timezone name. I need to get the timezone abbreviation.

> For example, GMT, UTC, PST, MST, CST, EST, etc...

Is this possible? The closest I've gotten is parsing the result of date.toString(), but even that won't give me an abbreviation. It gives me the timezone's long name.

A native solution:

var zone = new Date().toLocaleTimeString('en-us',{timeZoneName:'short'}).split(' ')[2]
console.log(zone)

https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Date/toLocaleDateString

You can pass undefined instead of en-us to default to the browser's current locale.

moment-timezone includes an undocumented method .zoneAbbr() which returns the time zone abbreviation. This also requires a set of rules which are available to select and download as needed.

Doing this:

<script src="moment.js"></script>
<script src="moment-timezone.js"></script>
<script src="moment-timezone-data.js"></script>
<script>
    moment().tz("America/Los_Angeles").zoneAbbr();
</script>

Returns:

'PDT' // As of this posting.

Edit (Feb 2018)

Evan Czaplicki has worked on a draft proposal to add a time zone API to browsers.

The Date object doesn't have a method for getting the timezone abbreviation, but it is implicit at the end of the result of toString. For example,

var rightNow = new Date();
alert(rightNow);

...will return something like Wed Mar 30 2011 17:29:16 GMT-0300 (ART). The timezone abbreviation can be isolated between parentheses:

var rightNow = new Date();
alert(String(String(rightNow).split("(")[1]).split(")")[0]);

The output will be the timezone abbreviation, like ART.

This works perfectly in Chrome, Firefox but only mostly in IE11. In IE11, timezones without straight forward abbreviations like "Indian Chagos Time" will return "ICT" instead of the proper "IOT"

var result = "unknown";
try{
    // Chrome, Firefox
    result = /.*\s(.+)/.exec((new Date()).toLocaleDateString(navigator.language, { timeZoneName:'short' }))[1];
}catch(e){
    // IE, some loss in accuracy due to guessing at the abbreviation
    // Note: This regex adds a grouping around the open paren as a
    //       workaround for an IE regex parser bug
    result = (new Date()).toTimeString().match(new RegExp("[A-Z](?!.*[\(])","g")).join('');
}
console.log(result);

Result:

"CDT"

Update for 2021

moment.js is now deprecated and they suggest using Luxon in new projects instead.

You can get a timezone abbreviation with Luxon like:

import { DateTime } from 'luxon'
DateTime.local().toFormat('ZZZZ') // => for ex: "PDT"

Note: The output format depends on the set locale. For more information see this answer.

I was able to achieve this with only moment.

moment.tz(moment.tz.guess()).zoneAbbr() //IST

Using contents from new Date().toString()

const timeZoneAbbreviated = () => {
  const { 1: tz } = new Date().toString().match(/\((.+)\)/);

  // In Chrome browser, new Date().toString() is
  // "Thu Aug 06 2020 16:21:38 GMT+0530 (India Standard Time)"

  // In Safari browser, new Date().toString() is
  // "Thu Aug 06 2020 16:24:03 GMT+0530 (IST)"

  if (tz.includes(" ")) {
    return tz
      .split(" ")
      .map(([first]) => first)
      .join("");
  } else {
    return tz;
  }
};

console.log("Time Zone:", timeZoneAbbreviated());
// IST
// PDT
// CEST

You can use the formatToParts method of Intl.DateTimeFormat to get the short time zone abbreviation. In certain parts of the world this may return strings like "GMT+8", rather than the abbreviation of an actual time zone name.

let timeZone = new Intl.DateTimeFormat('en-us', { timeZoneName: 'short' })
  .formatToParts(new Date())
  .find(part => part.type == "timeZoneName")
  .value
console.log(timeZone)

You can use the Native Javascript date object. Just hardcode the long timezone name 'America/Los_Angeles.

var usertimezone = 'America/Los_Angeles';
var usertimezoneabbreviation = new Date().toLocaleTimeString('en-us',{timeZone: usertimezone, timeZoneName:'short'}).split(' ')[2];

console.log(usertimezoneabbreviation); //PDT

If all else fails, you can simply create your own hashtable with the long names and abbreviations.

Updated for 2015:

jsTimezoneDetect can be used together with moment-timezone to get the timezone abbreviation client side:

moment.tz(new Date(), jstz.determine().name()).format('z');  //"UTC"

Moment-timezone cannot do this on it's own as its function which used to handle this was depreciated because it did not work under all circumstances: https://github.com/moment/moment/issues/162 to get the timezone abbreviation client side.

For a crossbrowser support I recommend using YUI 3 Library:

Y.DataType.Date.format(new Date(), {format:"%Z"});

It supports strftime identifiers.

For more information: http://yuilibrary.com/yui/docs/datatype/#dates

I know the problem remains of differences between browsers, but this is what I used to get in Chrome. However it is still not an abbreviation because Chrome returns the long name.

new Date().toString().replace(/^.*GMT.*\(/, "").replace(/\)$/, "")

Not possible with vanilla JavaScript. Browsers are inconsistent about returning timezone strings. Some return offsets like +0700 while others return PST.

It's not consistent or reliable, which is why you need 3rd party script like moment.js (and moment-timezone.js) or create your own hashtable to convert between offsets and timezone abbreviations.

This is a tricky subject. From what I gather the timezone is not embedded as part of the Date object when it's created. You also cannot set the timezone for a Date object. However, there is a timezone offset you can get from a Date object which is determined by the user's host system (timezone) settings. Think of timezone as a way to determine the offset from UTC.

To make life easier, I highly recommend moment and moment-timezone for handling these things. Moment creates a wrapper object for Date with a nice API for all kinds of things.

If an existing date object is supplied to you through some parameter or something, you can pass it the constructor when creating a the moment object and you're ready to roll. At this point you can use moment-timezone to guess the user's timezone name, and then use moment-timezone formatting to get the abbreviation for the timezone. I would venture to say that most users have their timezone set automatically but you shouldn't rely on this for 100% accuracy. If needed you can also set the timezone you want to use manually before pulling the format you need.

In general when working with date and time it's best to store UTC in your database and then use moment js to format the time for the user's timezone when displaying it. There may be cases where you need to be sure the timezone is correct. For example if you are allowing a user to schedule something for a specific date and time. You would need to make absolutely sure that with a west coast user that you set the timezone to PDT/PST before converting to UTC for storage in your database.

Regarding the timezone abbreviation...
Here is a basic example to get the timezone abbreviation using moment and moment-timezone.

// if all you need is the user's timezone abbreviation you don't even need a date object.
const usersTimezoneName = moment.tz.guess()
const timezoneAbbr = moment().tz(usersTimezoneName).format('z')
console.log(timezoneAbbr) // PST (depending on where the user is)

// to manually set the timezone
const newYorkAbbr = moment(dateObj).tz('America/New_York').format('z')
console.log(newYorkAbbr) // EST

For displaying a specific date object with offsets for a specific timezone you can do this.

const xmas = new Date('December 25, 2017 16:20:00')
const losAngelesXmas = moment(xmas).tz('America/Los_Angeles')
console.log(losAngelesXmas.format("dddd, MMMM Do YYYY, h:mm:ss a")) // Monday, December 25th 2017, 4:20:00 pm

Try this function

function getTimezoneAbbreviation(date) {
  // Convert the date into human readable
  // An example: Fri Jul 09 2021 13:07:25 GMT+0200 (Central European Summer Time)
  // As you can see there is the timezone

  date = date.toString();

  // We get the timezone matching everything the is inside the brackets/parentheses
  var timezone = date.match(/\(.+\)/g)[0];

  // We remove the brackets/parentheses
  timezone = timezone.replace("(", "").replace(")", "");

  // A new variable for the abbreviation
  var abbreviation = "";

  // We run a forEach dividing the timezone in words with split
  timezone.split(" ").forEach((word) => {

      // We insert the first letter of every word in the abbreviation variable
      abbreviation += word.split("")[0];

  });

  // And finally we return the abbreviation
  return abbreviation;
}

Try Google's Closure Class goog.i18n.DateTimeSymbols and their locale related classes.

Here is a JavaScript self-updating, 12-hour format date/time display that doesn't quite answer the question, however it may help others as it is related and builds on Stephen DuMont's solution and MDN link. W3 Schools had a very helpful tutorial, and real-time updates do not require page refresh.

Tests with the latest versions of desktop FireFox, Chrome, Opera, and Internet Explorer 11 all work. The "2-digits" hour only appears to prefix a zero for single values in IE, however the minutes return a 2-digit value reliably for all browsers. Tests with discontinued Windows Safari work although 12-hour format is ignored and seconds are not hidden.

The function includes the local timezone, as well adjustable options for fall-back languages, day and date display, and 12/24 hour format. Date and time were split to add the separating 'at' string. Setting only 'toLocaleTimeString' with select options will also return both date and time. The MDN pages can be referenced for options and values.

<!--
function dateTimeClock() {
  var date = new Date();
  document.getElementById('timedate').innerHTML = date.toLocaleDateString(['en-us', 'en-GB'], {
      weekday: 'long',
      month: 'long',
      day: '2-digit',
      year: 'numeric'
    }) + ' at ' +
    date.toLocaleTimeString(['en-us', 'en-GB'], {
      hour12: 'true',
      hour: '2-digit',
      minute: '2-digit',
      timeZoneName: 'short'
    });
  var t = setTimeout(dateTimeClock, 500);
}

function start() {
  dateTimeClock();
}
window.onload = start;
//-->

<div id="timedate"></div>

import { tz } from 'moment-timezone';
import * as moment from 'moment';

const guess = tz.guess(true);    // "Asia/Calcutta"
const zone = tz.zone(guess);     // return Zone object 
zone.abbr(new Date().getTime())  // "IST" 
// once u pass timestamp it'll return timezone abbrevation.

try {
    result = /.*\s(.+)/.exec(date.toLocaleDateString(navigator.language, {timeZoneName:'short' }))[1];
} catch(e) {
    result = (new Date()).toTimeString().match(new RegExp("[A-Z](?!.*[\(])","g")).join('');
}

console.log(result);