# Get the timezone string

Read the runtime’s IANA time zone, such as America/Sao_Paulo.

Canonical: https://1loc.dev/date-time/get-the-timezone-string/
Version: 1.0.0
Runtime: JavaScript · Node.js 22 / modern browsers
Verification: Usage lines executed in Node.js 22 and headless Chromium; no external services
Updated: 2026-10-28

## Implementation

```javascript
function getTimezone() { return Intl.DateTimeFormat().resolvedOptions().timeZone; }
```

## Usage

```javascript
getTimezone(); // e.g. 'America/Sao_Paulo'
const at = new Date('2026-10-28T12:00:00Z');
at.toLocaleTimeString('en-GB', { timeZone: 'America/Sao_Paulo', hour: '2-digit', minute: '2-digit' }); // → '09:00'
at.toLocaleTimeString('en-GB', { timeZone: getTimezone(), hour: '2-digit', minute: '2-digit' }); // e.g. '09:00'
```

Lines marked → were executed in Node.js 22 and in headless Chromium, and each result was compared with the value shown. Lines marked e.g. are illustrative.

## Limits

- Returns the zone of the runtime: the visitor’s in a browser, the server’s (often UTC) in Node.js. Store instants in UTC and convert for display.
- A zone is not an offset: America/Sao_Paulo has had no daylight saving time since 2019, while other zones still shift twice a year.

The function does not validate its arguments. Add checks where it receives untrusted input.

## Source and license

Original: https://github.com/phuocng/1loc/blob/14b481cf60dff1620ab1bb99a43b1f68068cdd9b/contents/get-the-timezone-string.mdx
Author: Nguyen Huu Phuoc and original contributors
Contributors: See original repository history
Source commit: 14b481cf60dff1620ab1bb99a43b1f68068cdd9b
Copyright (c) 2020 phuoc-ng
License: MIT — https://1loc.dev/licenses/
Maintainer: Oveyon
Modifications: Documented as a reference with executed usage lines. Original MDX retained as inert source evidence.