Chatham Daylight Time (CHADT)

UTC offset: +13:45 (during DST)
Standard offset: +12:45 (CHAST)
IANA identifier: Pacific/Chatham
Abbreviation: CHADT
Population: approximately 600
DST period: Last Sunday in September to first Sunday in April (NZ schedule)

Chatham Daylight Time shifts the Chatham Islands forward one hour from +12:45 to +13:45 during summer. This is one of the world's most unusual time offsets: a 45-minute departure from the nearest whole hour, maintained for a community of about 600 people on a remote archipelago 800 km east of New Zealand's South Island.

At +13:45 during DST, Chatham time is 45 minutes ahead of mainland New Zealand Daylight Time (NZDT, +13:00). This means when Auckland says "2:00 p.m.," the Chathams say "2:45 p.m." The offset applies year-round: standard time is also 45 minutes ahead of the mainland.

Why 45 Minutes?

The Chatham Islands sit at about 176W longitude, roughly 15 degrees east of mainland New Zealand. Solar time there is about 1 hour ahead of Wellington. The 45-minute offset was a compromise: close to the natural solar difference but not a full hour that would create more scheduling difficulties with the mainland. The offset was informally established around 1945 and legislated in 1974.

The Islands

• Chatham Island (the main island): About 900 km2, sparsely vegetated, rolling terrain
• Pitt Island: Smaller, across Pitt Strait
• Several islets (uninhabited)

The landscape is windswept and exposed. Trees struggle in the persistent westerly winds. The islands are known for endemic species (Chatham Island black robin, brought back from extinction with a population of 5 birds in 1980; Chatham Island forget-me-not).

Waitangi

The main settlement (~200 people). A fishing village/township with a school, general store, and hotel. The fishing industry (crayfish/lobster, blue cod, paua/abalone) is the primary economy. Some sheep/cattle farming. Limited tourism (expensive to reach, accommodations sparse).

The Moriori

The original inhabitants, a Polynesian people related to but distinct from mainland Maori. The Moriori developed a pacifist culture on the islands, renouncing warfare through the covenant of Nunuku. In 1835, Maori from mainland New Zealand invaded, enslaved, and killed much of the Moriori population. The community nearly went extinct. Today about 700 people identify as Moriori, mostly living off-island, and cultural revival efforts are active.

Climate

Cool maritime oceanic:

• Summer (January): 14-18C
• Winter (July): 5-10C
• Rainfall: ~800 mm
• Wind: constant, strong westerlies
• Fog: frequent

Technical Identifiers

• Pacific/Chatham (IANA canonical)
• CHADT (Chatham Daylight Time)
• CHAST (Chatham Standard Time, +12:45)
• Windows: "Chatham Islands Standard Time"
• DST: NZ schedule (last Sunday September to first Sunday April)
• Always 45 minutes ahead of NZ mainland

Quick Reference