I can't set a default timezone on windows.

[Claud]

This code works well on Linux but does not work on windows.

process.env.TZ = 'UTC';
console.log(new Date());

On windows i see timezone from my os.

Thu Dec 10 2015 14:28:45 GMT+0300

[bnoordhuis]

Does it work when you set TZ on the command line? V8 calls _tzset() on Windows, which respects TZ, but it runs quite early on.

The same caveat applies to Unices; the fact that setting TZ inside the program works is luck more than anything else. If you want it to be reliable and future proof, run your program with env TZ=UTC node app.js.

[Claud]

@bnoordhuis Yes, I tried to set an environment variable, set "TZ=UTC" is not work.

[bnoordhuis]

What version of Windows is that? Do you get correct output after tzutil /s UTC?

[Claud]

Windows 10x64

Thu Dec 10 2015 12:42:57 GMT+0000

It works, but it changes the time zone of the OS.

[bnoordhuis]

It works, but it changes the time zone of the OS.

Right, but it confirms that the timezone calculation as such is correct once it has the right timezone.

/cc @nodejs/platform-windows - I'm fairly sure it's a V8 issue (relevant code here) but maybe you can take a look?

[seishun]

Is it even supposed to work the way it does on Linux? Is it documented anywhere?

[bnoordhuis]

V8 documentation? Surely you jest! If you're referring to _tzset(), MSDN claims it honors TZ.

[seishun]

No, I'm referring to how the TZ variable affects the behavior of new Date() in Node.js.

[seishun]

Correction: new Date() is not affected, the implicit toString() call is.

[bnoordhuis]

Neither we nor V8 document the effect of TZ, it's an artifact of the implementation.

[seishun]

If you're referring to _tzset(), MSDN claims it honors TZ.

GetTimeZoneInformation, however, does not - and that's where V8 gets timezone information from. I'm not sure if there is any point to the _tzset() call at all.

[jasnell]

Closing as there does not appear to be anything for us to do in core on this. Can reopen if necessary.

[pankleks]

Hello,

I've been struggling with same problem.
Under windows, TZ setting is not respected, zone is taken from user which runs app.
Under Linux it works as expected.

I'm running production enviroment where I can't change zone for user - what should I do?

Thanks!

[capaj]

@pankleks the only solution I've come up for windows is: https://github.com/capaj/set-tz

[smokinjoe]

This problem still exists two years later.

[danielbayerlein]

I've created a ugly batch script for this issue.

package.json

"scripts": {
  "test": "jest",
  "test:win": "bin/test.cmd"
}

bin/test.cmd

FOR /F "tokens=* USEBACKQ" %%F IN (`tzutil /g`) DO SET PREVIOUS_TZ=%%F
tzutil /s "UTC"
cmd.exe /c yarn test
tzutil /s "%PREVIOUS_TZ%"

[jasnell]

Ok, updated #38642

it now supports setting TZ before running the node.js process and during...

$ set TZ="America/New_York"
$ node -pe "new Date().toString()"

process.env.TZ = 'Etc/UTC'
console.log(new Date().toString());

[srl295]

Ok, then yeah, it would appear that we'll have to do this mapping ourselves. @srl295 ... is there an API in ICU to map timezone identifiers like "EST" to the identifier expected by TimeZone::createTimeZone()

As i noted in the PR, EST should be strongly discouraged. It's also almost certainly not what you want. (the east coast of n. america is in daylight time right now, EST will give the wrong result for example). if we do anything (such as in the pr) it should be advertised as using tz ids only, everything else is undefined results.

[WiXSL]

I can confirm this problem is solved in node version 17.0.1 using Windows 10

[pavelmickevic]

thank you for the fix 16cb4f7

I can confirm this problem is solved in node version 17.0.1 using Windows 10

works now:

node -v
v17.2.0

OS Name: Microsoft Windows 10 Pro
OS Version: 10.0.19041 N/A Build 19041

-console.log({ tz: process.env.TZ, offset: moment().utcOffset() }); // { tz: 'UTC', offset: 120 } # bad
+console.log({ tz: process.env.TZ, offset: moment().utcOffset() }); // { tz: 'UTC', offset: -0 } # good

[tmeindle]

Could the fix for this issue be backported to Node 16 LTS?

[richardlau]

Could the fix for this issue be backported to Node 16 LTS?

#38642 was included in Node.js 16.2.0.

[phalgunv]

Is this fix available on Node.js v14?

[richardlau]

Is this fix available on Node.js v14?

No, it was not backported to Node.js v14.

[phalgunv]

What can be done to get it ported back to v14?

[targos]

Nothing. v14 is out of support now.

[NisuSan]

Not working if send the timesatamp to contructor

$ node -pe "new Date(1685389932472)"
2023-05-29T19:52:12.472Z

$ node -pe "new Date()"
2023-05-29T20:21:51.841Z 

$ set TZ="Europe/Kiev" && node -pe "new Date(1685389932472)" #still not working
2023-05-29T19:52:12.472Z

But timesatmp is Mon May 29 2023 22:52:12 GMT+0300 (Eastern European Summer Time)

[mattjohnsonpint]

@NisuSan - Time zones don't change the UTC representation of a timestamp.

[NisuSan]

@mattjohnsonpint Hmm, in browser it works fine. Any way, can you explain how to deal with timestamp and time zone in this case?

[mattjohnsonpint]

@NisuSan - The Z at the end of the ISO 8601 / RFC 3339 formatted string represents "Zulu" time - which is another term for "UTC". Unix timestamps are also in terms of UTC (being the number of seconds or milliseconds since 1970-01-01T00:00:00.000Z). UTC is irrespective of time zones, thus time zones do not affect UTC output.

If you're asking why you see UTC output instead of local output, that's because you're just printing a raw Date object. You didn't call any function on it that creates a string. Unfortunately, the implementation of printing a raw Date object is undefined. Some environments print the UTC representation (as if you printed the result of calling the toISOString function), and other environments print the local time representation (as if you printed the result of calling the toString function).

I have asked for standardization of this, to avoid the type of confusion you encountered, but with no result. See whatwg/console#132

[mattjohnsonpint]

If you want to see the effect of the system time zone, and Node's support for changing it, then you'll need to call toString - not just print the raw Date object.

on Windows:

set TZ=Europe/Kiev && node -pe "new Date(1685389932472).toString()"
Mon May 29 2023 22:52:12 GMT+0300 (Eastern European Summer Time)

Note: Make sure there are no quotes around the ID on Windows.

or on Linux / macOS :

TZ="Europe/Kiev" node -pe "new Date(1685389932472).toString()"
Mon May 29 2023 22:52:12 GMT+0300 (Eastern European Summer Time)

[NisuSan]

@mattjohnsonpint Great explanation, thanks!