Tonga time zone history
Mean solar time at Tongatapu is about UTC−11:41, so the clock on UTC+13 runs a calendar day ahead of the sun, plus 41 minutes. Tongatapu kept local mean time (UTC+12:19:12) until 1945, the fifth-latest switch of the 298 zones with local mean time in the record. Daylight saving time was used in 6 years since 1970, last in 2017; under the current rules the clocks no longer change.
UTC+13
Standard time is UTC+13 all year under the current rules.
Summer time in 6 of 57 years since 1970
Before 1970
Standard time changes
| Date | Change | New standard time | Clock label |
|---|---|---|---|
| Before 1970 | |||
| September 10, 1945 | Local mean time (UTC+12:19:12) replaced | UTC+12:20 | numeric only |
| January 1, 1961 | Standard time forward 40 minutes | UTC+13 | numeric only |
Daylight saving periods
| Years | Clocks go forward | Clocks go back | Shift and labels |
|---|---|---|---|
| 1999 | October 7 | not that year | 1 hour |
| 2000 | November 5 | March 19 | 1 hour |
| 2001 | November 4 | January 28 | 1 hour |
| 2002 | not that year | January 27 | 1 hour |
| 2016 | November 6 | not that year | 1 hour |
| 2017 | not that year | January 15 | 1 hour |
Also on UTC+13
Clocks next door since 1970
- Niue (600 km): usually 24 hours behind; different on 402 days in 1999–2002, 2016 and 2017.
- Fiji (747 km): usually 1 hour behind; different on 1,242 days in 1998–2002 and 2009–2021.
- Samoa (891 km): usually 24 hours behind; different on 6,097 days in 1999–2002 and 2010–2026; same time today.
- American Samoa (900 km): usually 24 hours behind; different on 402 days in 1999–2002, 2016 and 2017.
- Tokelau (1,376 km): usually 24 hours behind; different on 5,812 days in 1999–2002 and 2011–2026; same time today.
How it compares
Standard time has stayed at UTC+13 since 1961.
On standard time, clocks in Tongatapu run 41 minutes ahead of local mean solar time.