Kailua, Big Island weather in September 2025

Expect 23°C daytime maximum temperatures in the shade with on average -9999 hours of sunshine per day in Kailua, Big Island in September. Check more long-term weather averages for Kailua, Big Island in September before you book your next holiday to Hawaii in 2025/2026.

  • 23°C maximum daytime temperature in September in Kailua, Big Island23
    23°C max day temperature
  • 15 days with some rainfall in September in Kailua, Big Island15
    15 days with some rainfall
  • 15°C minimum night-time temperature in September in Kailua, Big Island15
    15°C min night temperature
  • 12 hours of daylight per day in September in Kailua, Big Island12
    12 hours of daylight per day
  • Moderate heat & humidity in September in Kailua, Big IslandM
    Moderate heat & humidity
  • 54 mm monthly rainfall in September in Kailua, Big Island54
    54 mm of monthly rainfall
  • UV (maximum) index 11+ (Extreme) in September in Kailua, Big Island11
    11+ (Extreme) UV index
  • 27°C sea temperature in September in Kailua, Big Island27
    27°C sea temperature

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The September weather guide for Hawaii (Kailua, Big Island) 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.

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

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How hot is it in Kailua, Big Island in September?

Daytime temperatures usually reach 23°C in Kailua, Big Island in September, falling to 15°C at night.

How warm is the sea around Kailua, Big Island in September?

The average sea temperature around Kailua, Big Island in September is 27°C.

Does it rain in Kailua, Big Island in September?

There are usually 15 days with some rain in Kailua, Big Island in September and the average monthly rainfall is 54mm.

Kailua, Big Island September sunrise & sunset times

Browse the sunrise and sunset times for Kailua, Big Island in September 2025. Select a month to view Kailua, Big Island sunrise and sunset times for the next 12 months.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Monday, 1st September 2025 06:09 18:39
Monday, 15th September 2025 06:12 18:26
Tuesday, 30th September 2025 06:15 18:12

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