Chatham Islands time zone history
Its standard time, UTC+12:45, is one of only 14 offsets among the 312 zones that are not a whole number of hours from UTC. Mean solar time at the Chatham Islands is about UTC−11:46, so the clock on UTC+12:45 runs a calendar day ahead of the sun, plus 31 minutes. The Chatham Islands left local mean time (UTC+12:13:48) in 1868, tied seventh-earliest switch among the 298 zones with local mean time in the record.
UTC+12:45
Standard time is UTC+12:45; clocks go forward to UTC+13:45 on the last Sunday in September and back on the first Sunday in April.
Summer time in 53 of 57 years since 1970
Before 1970
Standard time changes
| Date | Change | New standard time | Clock label |
|---|---|---|---|
| Before 1970 | |||
| November 2, 1868 | Local mean time (UTC+12:13:48) replaced | UTC+12:15 | numeric only |
| January 1, 1946 | Standard time forward 30 minutes | UTC+12:45 | numeric only |
Daylight saving periods
| Years | Clocks go forward | Clocks go back | Shift and labels |
|---|---|---|---|
| 1974 | November 3 | not that year | 1 hour |
| 1975 | October 26 | February 23 | 1 hour |
| 1976–1988 | last Sunday in October, 02:45 | first Sunday in March, 03:45 | 1 hour |
| 1989 | October 8 | March 5 | 1 hour |
| 1990–2006 | first Sunday in October, 02:45 | third Sunday in March, 03:45 | 1 hour |
| 2007 | September 30 | March 18 | 1 hour |
| 2008–2037 | last Sunday in September, 02:45 | first Sunday in April, 03:45 | 1 hour |
Clock changes in 2026, 2027 and 2028
The clocks go forward 1 hour on September 27, 2026, September 26, 2027 and September 24, 2028 at 02:45 and back 1 hour on April 5, 2026, April 4, 2027 and April 2, 2028 at 03:45, local time.
Clocks next door since 1970
- Auckland (1,076 km): always 45 minutes behind.
- Macquarie Island (Australia) (2,114 km): usually 2 hours 45 minutes behind; different on 1,250 days in 1970–2026.
- Norfolk Island (2,151 km): usually 1 hour 15 minutes behind; different on 10,400 days in 1974–2026; 1 hour 45 minutes behind today.
- Lord Howe Island (Australia) (2,533 km): usually 2 hours 45 minutes behind; different on 11,090 days in 1974–2026; 2 hours 15 minutes behind today.
- Tonga (2,540 km): usually 15 minutes ahead; different on 8,164 days in 1974–2026.
How it compares
Under the current rules, summer time lasts 190 days in 2027, tied second-longest among the 11 zones in Oceania with summer time.
Standard time has stayed at UTC+12:45 since 1946.
On standard time, clocks in the Chatham Islands run 31 minutes ahead of local mean solar time.