Seattle weather in September 2025

Expect 70°F daytime maximum temperatures in the shade with on average 7 hours of sunshine per day in Seattle in September. Check more long-term weather averages for Seattle in September before you book your next holiday to Washington State in 2025/2026.

  • 70°F maximum daytime temperature in September in Seattle70
    70°F max day temperature
  • 7 hours of sunshine per day
  • 9 days with some rainfall in September in Seattle9
    9 days with some rainfall
  • 52°F minimum night-time temperature in September in Seattle52
    52°F min night temperature
  • 13 hours of daylight per day in September in Seattle13
    13 hours of daylight per day
  • No heat & humidity in September in Seattle0
    No heat & humidity
  • 1.9 inches monthly rainfall in September in Seattle1.9
    1.9 inches of monthly rainfall
  • UV (maximum) index 5 (Moderate) in September in Seattle5
    5 (Moderate) UV index

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The September weather guide for Washington State (Seattle) 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)  |  Imperial (°F)

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How hot is it in Seattle in September?

Daytime temperatures usually reach 70°F in Seattle in September, falling to 52°F at night.

How sunny is it in Seattle in September?

There are normally 7 hours of bright sunshine each day in Seattle in September - that's 57% of daylight hours.

Does it rain in Seattle in September?

There are usually 9 days with some rain in Seattle in September and the average monthly rainfall is 1.9 inches.

Seattle September sunrise & sunset times

Browse the sunrise and sunset times for Seattle in September 2025. Select a month to view Seattle sunrise and sunset times for the next 12 months.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Monday, 1st September 2025 05:28 18:49
Monday, 15th September 2025 05:47 18:21
Tuesday, 30th September 2025 06:08 17:50

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