Cook Islands weather in September 2025

Expect 26°C daytime maximum temperatures in the shade with on average -9999 hours of sunshine per day in Cook Islands in September. Check more long-term weather averages for Cook Islands in September before you book your next holiday to Cook Islands in 2025/2026.

  • 26°C maximum daytime temperature in September in Cook Islands (Avarua)26
    26°C max day temperature
  • 5 days with some rainfall in September in Cook Islands (Avarua)5
    5 days with some rainfall
  • 19°C minimum night-time temperature in September in Cook Islands (Avarua)19
    19°C min night temperature
  • 12 hours of daylight per day in September in Cook Islands (Avarua)12
    12 hours of daylight per day
  • Low heat & humidity in September in Cook Islands (Avarua)L
    Low heat & humidity
  • 132 mm monthly rainfall in September in Cook Islands (Avarua)132
    132 mm of monthly rainfall
  • UV (maximum) index 10 (Very High) in September in Cook Islands (Avarua)10
    10 (Very High) UV index
  • 24°C sea temperature in September in Cook Islands (Avarua)24
    24°C sea temperature

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The September weather guide for Cook Islands (Avarua) shows long term weather averages processed from data supplied by CRU (University of East Anglia), the Met Office & the Netherlands Meteorological Institute. Find out more about our data sources.

Top Cook Islands destinations

Below are average maximum temperatures at popular countries, regions and places in the Cook Islands in September. Select a holiday destination to see more weather parameters.

All Cook Islands destinations

Metric (°C / mm)  |  Imperial (°F / inches)

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How hot is it in the Cook Islands in September?

Daytime temperatures usually reach 26°C in Avarua, Cook Islands in September with low heat and humidity, falling to 19°C at night.

How warm is the sea around the Cook Islands in September?

The average sea temperature around Avarua, Cook Islands in September is 24°C.

Does it rain in the Cook Islands in September?

There are usually 5 days with some rain in Avarua, Cook Islands in September and the average monthly rainfall is 132mm.

Cook Islands September sunrise & sunset times

Browse the sunrise and sunset times for Cook Islands in September 2025. Select a month to view Cook Islands sunrise and sunset times for the next 12 months. The Cook Islands sunrise and sunset times shown below are for Avarua.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Monday, 1st September 2025 06:48 18:30
Monday, 15th September 2025 06:35 18:34
Tuesday, 30th September 2025 06:21 18:37

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