Rarotonga & the Cook Islands Weather in January

Last Updated: 16 June, 2025

What is the Weather Like in Rarotonga and the Cook Islands in January?

Planning on exploring the Cook Islands in January? You would be one of the few who choose to visit the Cook Islands during this time, which is ideal for savvy travellers looking to get the best travel deals and experience the islands all to themselves! Temperatures are hot and humid, making it all the more refreshing when taking part in the Cooks’ water activities.

What deters many travellers, however, is the label of the “wet season”, with a higher chance of rainfall and a slight risk of cyclones. But knowing that rain can occur at any time of the year in Rarotonga and the Cook Islands, you might just think that January is just as good as any month to visit the islands… Find out more about the Rarotonga and Cook Islands weather in January below!

Before we jump into this weather guide for January, be sure to bookmark Rarotonga & the Cook Islands Weather, Seasons & Climate, as well as The Best Time to Visit Rarotonga & the Cook Islands for more advice.

6 Tips for Visiting the Cook Islands in January

Due to the high UV levels during January, make sure you wear high-factor (and reef-safe) sunscreen.
Pack insect repellent! Mosquitoes are more active during the wet season. Check out the 10 Ways to Avoid Mosquito Bites in the Cook Islands for tips.
Note that January 1 and 2 are public holidays in the Cook Islands, so expect shops and some businesses to be closed.
While January is hot and humid, remember that there are plenty of ways to cool down, thanks to the Cook Islands’ array of water sports, oceans and some resorts having swimming pools – check out the 10 Best Water Activities in Rarotonga & the Cook Islands for inspiration.
January is the low season in the Cook Islands, so don’t worry about booking accommodation too far in advance. However, be sure to double-check which activities are available during the low season to avoid disappointment.
Allow extra time to travel between islands, as flights can get cancelled due to bad weather.

Rarotonga & the Cook Islands Weather in January

Typical Temperatures in January

In the Cook Islands’ “summer season”, January is one of the warmest months. Temperatures typically reach 28°C (82°F) during the day, while the lowest temperatures are around 23°C (74°F) – usually at night. January also experiences high humidity, which can make it feel slightly warmer than it actually is.

Temperatures Across the Cook Islands

Rarotonga – The average maximum temperature is 28°C (82°F) and the minimum average temperature is 23°C (74°F)
Aitutaki – The average maximum temperature is 30°C (86°F) and the minimum average temperature is 24°C (75°F)
Mangaia – The average maximum temperature is 29°C (84°F) and the minimum average temperature is 23°C (74°F)
Mitiaro – The average maximum temperature is 29°C (85°F) and the minimum average temperature is 24°C (75°F)
Manihiki (North) – The average maximum temperature is 30°C (86°F) and the minimum average temperature is 24°C (75°F)
Penrhyn (North) – The average maximum temperature is 31°C (89°F) and the minimum average temperature is 25°C (77°F).

Sea Temperature in January

The Cook Islands experiences warm waters year-round. However, January is one of the months when sea temperatures in Rarotonga and the Cook Islands are at their highest. Sea temperatures average 27°C (81°F) in January.

Hours of Sun in January

Many travellers visiting Rarotonga and the Cook Islands want to see some sun! January is a great time to soak up the sun, with an average of 6 hours 24 mins of bright sunshine each day. Plus, the Cook Islands experiences some of its longest days with daylight hours being an average of 13 hours.

UV Levels During January

Wearing sunscreen is recommended all year round in the Cook Islands, but especially in January when the maximum UV levels are at an extreme around midday! UV levels are 11+ UV index at midday.

For advice on what sunscreen to wear, see our The Best Sunscreens for the Cook Islands + Sun Protection Tips.

Sunrise and Sunset During January

January has daylight hours lasting about 13 hours a day in the Cook Islands.

Sunrise: 6:00 am at the beginning of January and 6:20 am at the end of January
Sunset: 7:24 pm at the beginning of January and 7:23 pm at the end of January.

Rainfall in January

January is a month of the “wet season” and, we’re not going to beat around the bush, it’s typically the wettest month of the year. Nevertheless, tropical rainfall patterns are usually swift, followed by sunshine.

If you need a rainy day backup for a couple of hours, check out the ideas in the 10 Things to Do in the Cook Islands on a Rainy Day.

The Cook Islands receives an average of 267 mm (10.5 in) of rainfall in the month of January, with around 17 days out of January experiencing rain.

Average Rainfall Across the Cook Islands

Rarotonga – The average rainfall in January is 267 mm (10.5 in)
Aitutaki – The average rainfall in January is 251 mm (9.9 in)
Mangaia – The average rainfall in January is 236 mm (9.3 in)
Mitiaro – The average rainfall in January is 205 mm (8 in)
Manihiki (North) – The average rainfall in January is 341 mm (13.4 in)
Penrhyn (North) – The average rainfall in January is 248 mm (9.8 in).

Tropical Storms in January

The South Pacific cyclone season starts in November and ends in April, making January a month with a higher risk of tropical storms. On average, less than 1 day in January in Rarotonga and the Southern Group is affected by tropical storms. Tropical storms are slightly more likely to affect the islands of the Northern Group.

Historically, the Cook Islands (including the Northern Group) was affected by a tropical cyclone in January 1845, 1865, 1905, 1914, 1941, 1944, 1950, 1955, 1956, 1958, 1959 and 1966. In more recent history, the Cook Islands saw minor beach erosion due to Cyclone Arthur (January 2007), while Cyclone Oli (January 2008) caused flooding in the Northern Group. In 2022, Cyclone Cody caused flooding on Rarotonga.

If you want to avoid the risk of cyclones in the Cook Islands, it’s best to travel in the dry season. For those planning to travel to the Cook Islands during January, be aware of what to do in the event of a cyclone alert by following our guide, Cyclone Safety in the Cook Islands.

Best Places to Visit in the Cook Islands in January

Apart from the first week of January, when locals return from the Cook Islands to celebrate the New Year with their families, January is a quiet time for tourists to experience the islands. With that in mind, you’re bound to have a great time no matter where you travel. But if we have to choose the best place to visit in the Cook Islands in January, it would be the following…

Aitutaki – If you’re looking for a little bit of drier weather than the main island (Rarotonga) and a stunning lagoon to cool off when the weather’s too hot, you might want to choose Aitutaki. The island group, just a 40+ minute flight from Rarotonga, is well equipped with accommodations and inviting lagoon cruises.

See what to do in Aitutaki in the 20 Best Things to Do on Aitutaki.

Mitiaro – The island in the Southern Group of the Cook Islands with the least rainfall, Mitiaro offers a drier climate in January than other destinations in the Cooks. If it’s too hot, you can always cool down in the refreshing cave pools on this raised coral atoll.

Find out more in the 15 Best Things to Do in Mitiaro.

January Packing List for Rarotonga and the Cook Islands

Be prepared for the Cook Islands in January by packing these few seasonal essentials:

High-factor reef-safe sunscreen
Rain jacket
Light cotton layers
Light long-sleeved tops (to cover from the sun and mosquitoes)
Light pants/trousers (to cover the knees when appropriate – church service, for example)
Sunhat
Sunglasses
Insect repellent
Swimwear
Closed walking shoes
Flip-flops/jandals/sandals
Sarong (pāreu)

Get more ideas on what to pack with our guide, What to Pack for Rarotonga & the Cook Islands: Cook Islands Packing List.

More About the Weather in Rarotonga and Cook Islands in January

That’s it for our complete guide to the weather and climate in Rarotonga and the Cook Islands in January. Check out the following articles for more weather advice:

Finally, enjoy a comprehensive guide to planning a trip to the Cook Islands in The Best Cook Islands Travel Guide.

Sources:

The information in this guide has been compiled from our extensive research, travel and experiences across the Cook Islands and the South Pacific, accumulated over more than a decade of numerous visits to each destination. Additional sources for this guide include the following:

Cook Islands Tourism Corporation (General travel advice - Updated [2025])
Cook Islands Tourism Industry Council (Tourism trade association - Updated [2025])
Ministry of Foreign Affairs and Immigration (Visa and immigration advice - Updated [2025])
Ministry of Finance & Economic Management (Border restrictions advice - Updated [2025])
Ministry of Agriculture (Biosecurity advice - Updated [2025])
Cook Islands Meteorological Service (Weather forecast and warnings - Updated [2025])
Cook Islands Statistics Office (Statistics and travel data - Updated [2025])
Ministry of Transport (Transport operators and licenses - Updated [2025])
SPTO (Pacific tourism advice - Updated [2025])
Safe Travel (New Zealand travel advisory for the Cook Islands - Updated [2025])
Smart Traveller (Australia travel advisory for the Cook Islands - Updated [2025])

At Cook Islands Pocket Guide, we uphold strict editorial standards to ensure accurate and quality content.

About the Author

Robin C.

This article was reviewed and published by Robin, the co-founder of Cook Islands Pocket Guide. He has lived, worked and travelled across 16 different countries before settling in the South Pacific, so he knows a thing or two about planning the perfect trip in this corner of the world. Robin works and consults regularly with Cook Islands Tourism Corporation, a local government body representing the tourism industry. Robin is also the co-founder of several other South Pacific travel guides and is a regular host of webinars with the South Pacific Tourism Organisation.

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