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.
🧭 How to Read Time Zones
Focus on the IANA ID, UTC offset, DST presence, and representative city.
Key terms
- ✅ IANA TZ ID: `Continent/City` (e.g., Asia/Tokyo). Avoid ambiguous abbreviations like JST/PST.
- ✅ UTC offset: difference from UTC (e.g., `+09:00`). Some regions change offsets during DST.
- ✅ DST: Daylight Saving Time; many regions move +1h during the DST period (e.g., America/New_York).
🌍 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 | ±00:00 | No | Coordinated Universal Time, baseline. |
💡 Operational Tips
Document the required TZ format and avoid ambiguous abbreviations.
Checklist
- 📝 Document that APIs/DBs should use IANA IDs; validate inputs accordingly.
- 📝 Show the offset (e.g., +09:00) alongside TZ in logs/UI.
- 📝 For DST regions, do arithmetic in UTC and apply TZ at render time.
- 📝 Lock TZ settings in containers/OS at deploy time to avoid unexpected locals.