Sea temperature in Cook Islands
Live water temperatures and swimming conditions across 5 beaches on the Cook Islands coast.
Best time to swim in Cook Islands
The sea in Cook Islands peaks in July, when the water averages around 23°C.
The main swimming season runs from January – December, when surface temperatures stay comfortable for extended sessions.
On average, 12 months a year sit above 20°C — the threshold most swimmers describe as pleasant without a wetsuit.
The coldest month is typically January at around 20°C, when cold-water swimmers dominate the coast.
Cook Islands sea temperature history
Long-term climatology for Cook Islands shows an annual mean sea temperature of 21°C, ranging from 20°C in winter to 23°C at the summer peak.
The seasonal swing is roughly 3°C between the coldest and warmest month — a useful yardstick when comparing years or checking whether the current sea is running above or below average.
Recent decades have trended slightly warmer at Cook Islands, in line with regional sea-surface temperature records for the wider basin.
Monthly averages below are drawn from multi-decadal climatology and are updated as new observations arrive.
Values are area averages; individual beaches vary by exposure and depth.
Cook Islands sea temperature: frequently asked questions
What is the warmest month to swim in Cook Islands?
July is the warmest month in Cook Islands, when the sea averages about 23°C. Late-season warmth often persists a few weeks after peak.
When is the sea coldest in Cook Islands?
The coldest month in Cook Islands is typically January, when the water averages around 20°C. Cold-water swimmers and surfers dominate this period.
When can you swim in Cook Islands without a wetsuit?
The main swimming season in Cook Islands runs from January – December — about 12 months a year when the sea sits above 20°C, the level most swimmers describe as pleasant without a wetsuit.
Do I need a wetsuit in Cook Islands?
Outside peak summer the water in Cook Islands drops toward 20°C, so a 3/2mm shorty or full wetsuit makes long swims much more comfortable. In peak months most swimmers go without.
What is the average sea temperature in Cook Islands?
The long-term annual mean sea temperature in Cook Islands is about 21°C, based on multi-decadal climatology of the surrounding waters.
How do I check the current sea temperature in Cook Islands?
The live reading at the top of this page shows the current sea temperature in Cook Islands, updated hourly from marine buoy and satellite data. The 7-day forecast covers water, air, waves, wind and UV for the week ahead.
Warmest beaches in Cook Islands right now
| Beach | Region | Sea | Swim score |
|---|---|---|---|
| Aitutaki Lagoon | Cook Islands | — | — |
| Muri Beach | Cook Islands | — | — |
| Muri Beach | Rarotonga | — | — |
| Titikaveka Beach | Rarotonga | — | — |
| Aitutaki Lagoon Beach | Aitutaki | — | — |