Time Zone List
Use IANA time zone IDs (e.g., Asia/Tokyo) instead of ambiguous abbreviations. Here are representative zones with offsets and DST presence.
๐งญ How to Read Time Zones
Focus on the IANA ID, UTC offset, DST presence, and representative city.
Key terms
- โ IANA TZ ID: `Continent/City` (e.g., Asia/Tokyo). Avoid ambiguous abbreviations like JST/PST.
- โ UTC offset: difference from UTC (e.g., `+09:00`). Some regions change offsets during DST.
- โ DST: Daylight Saving Time; many regions move +1h during the DST period (e.g., America/New_York).
๐ Representative Time Zones
This is a small subset; real-world usage should rely on the specific IANA ID.
List (selected)
| IANA ID | UTC offset (standard) | DST | Notes |
|---|---|---|---|
| Asia/Tokyo | +09:00 | No | Japan; no DST. |
| Asia/Seoul | +09:00 | No | Korea; no DST. |
| Asia/Shanghai | +08:00 | No | China Standard Time. |
| Asia/Taipei | +08:00 | No | Taiwan Standard Time. |
| Asia/Singapore | +08:00 | No | Singapore Time. |
| Australia/Sydney | +10:00 | Yes (varies by state) | Goes to +11:00 during DST; check per state. |
| Europe/London | +00:00 | Yes | BST during DST (+01:00). |
| Europe/Berlin | +01:00 | Yes | CET/CEST; +02:00 during DST. |
| Europe/Paris | +01:00 | Yes | CET/CEST; +02:00 during DST. |
| America/New_York | -05:00 | Yes | EST/EDT; -04:00 during DST. |
| America/Chicago | -06:00 | Yes | CST/CDT; -05:00 during DST. |
| America/Denver | -07:00 | Yes | MST/MDT; -06:00 during DST. |
| America/Los_Angeles | -08:00 | Yes | PST/PDT; -07:00 during DST. |
| America/Phoenix | -07:00 | No | Arizona; does not observe DST. |
| America/Sao_Paulo | -03:00 | No (recent years) | Had DST in the past; check current rules. |
| UTC | ยฑ00:00 | No | Coordinated Universal Time, baseline. |
๐ก Operational Tips
Document the required TZ format and avoid ambiguous abbreviations.
Checklist
- ๐ Document that APIs/DBs should use IANA IDs; validate inputs accordingly.
- ๐ Show the offset (e.g., +09:00) alongside TZ in logs/UI.
- ๐ For DST regions, do arithmetic in UTC and apply TZ at render time.
- ๐ Lock TZ settings in containers/OS at deploy time to avoid unexpected locals.