Time zone · Oceania

CIST

Cook Islands Standard Time

Cook Islands Standard Time (CIST) is UTC-10:00 all year and covers the whole of the Cook Islands, including Rarotonga. The islands have not used daylight saving time since 1991 and share Hawaii’s clock.

UTC-10:00 standard1 IANA zone1 city
Current time in CIST☀ Daylight
13:03:36

Wednesday, October 14, 2026

06:0812:2518:41
Standard
-10 · −10
IANA zones
1

Current offset

UTC-10:00

Standard · -10

Daylight saving

Not observed

Year-round standard time

IANA zones

1

None observe daylight saving

DST offset

—

No summer variant

About CIST

A fixed, year-round offset.

Cook Islands Standard Time (CIST) is UTC-10:00 all year and covers the whole of the Cook Islands, including Rarotonga. The islands have not used daylight saving time since 1991 and share Hawaii’s clock.

IANA zones · the technical identifiers

The zone that resolve to CIST.

For software, always store the IANA identifier — never the abbreviation alone. The database keeps these zones distinct because their rules can, and historically did, diverge.

IANA zonePrimary cityDST
Pacific/RarotongaRarotonga— None

Cities across CIST

Local time, city by city.

1 city

Avarua
13:03
13:03:37 · -10
CIST year-round

Where CIST is used

One country.

Cook Islands
Polynesia

Same offset · UTC-10:00

Other zones at UTC-10:00 right now.

These named zones share CIST's offset today. When daylight saving rules differ, they drift apart for part of the year.

HSTUTC−10
--:--
Hawaii-Aleutian Standard Time
Americas▲ Observes DST
United States
TAHITIUTC−10
--:--
Tahiti Time
Oceania— No DST
French Polynesia

Convert

CIST to the world's clocks.

Open the converter →
Cook Islands Standard Time
1:03pm
Eastern Daylight Time
7:03pm
Cook Islands Standard Time to Eastern Time6 hours behind
Cook Islands Standard Time
1:03pm
Pacific Time
4:03pm
Cook Islands Standard Time to Pacific Time3 hours behind
Cook Islands Standard Time
1:03pm
British Summer Time
12:03am
Cook Islands Standard Time to London (GMT)11 hours behind
Cook Islands Standard Time
1:03pm
Central European Time
1:03am
Cook Islands Standard Time to Central Europe12 hours behind
Cook Islands Standard Time
1:03pm
India Standard Time
4:33am
Cook Islands Standard Time to India15 hours 30 minutes behind
Cook Islands Standard Time
1:03pm
Japan Standard Time
8:03am
Cook Islands Standard Time to Japan19 hours behind

Frequently asked questions

Common questions about CIST, daylight saving, and how to handle it in software. Can't find what you need? Email [email protected].

Which places share the Cook Islands’ clock?
Hawaii and Tahiti in French Polynesia also use UTC-10:00 all year, so they show the same time as Rarotonga. Samoa, across the International Date Line at UTC+13:00, is 23 hours ahead.
Has the Cook Islands’ time changed in the past?
Yes. The islands used UTC-10:30 until November 1978, then switched to UTC-10:00 with a half-hour daylight saving shift to UTC-09:30 each summer. Summer time ended in March 1991, and the clock has stayed at UTC-10:00 since.
Does the Cook Islands use daylight saving time?
No. The islands have stayed on UTC−10:00 all year since March 1991.
How far behind New Zealand are the Cook Islands?
Rarotonga is 22 hours behind Auckland in the New Zealand winter and 23 hours behind while New Zealand is on daylight saving time, so 10:00 on Monday in Rarotonga is 08:00 or 09:00 on Tuesday in Auckland.

Source: IANA tzdb2026d · Reviewed

Free · Developer API

This time zone, as JSON.

Its defining offset, DST status and member counts, from one endpoint.

GET /v1/abbreviations Live

Also in the API: time zones by coordinates, conversions that flag daylight saving gaps, and abbreviations decoded.

Get your free API key → All endpoints Plans and pricing

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// CIST, by slug (codes can be shared)
GET /v1/abbreviations/cook-islands-standard-time
{
"data": {
"code": "CIST",
"name": "Cook Islands Standard Time",
"counts": { "timezones": 1, "countries": 1 },
…
}
}