Seattle weather in September 2025

Expect 21°C 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.

  • 21°C maximum daytime temperature in September in Seattle21
    21°C max day temperature
  • 7 hours of sunshine per day
  • 9 days with some rainfall in September in Seattle9
    9 days with some rainfall
  • 11°C minimum night-time temperature in September in Seattle11
    11°C 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
  • 49 mm monthly rainfall in September in Seattle49
    49 mm of monthly rainfall
  • UV (maximum) index 5 (Moderate) in September in Seattle5
    5 (Moderate) UV index

More about Seattle

Seattle by month

Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

Recommended for Washington State

Holiday Autos discount code: up to 10% off global car hire

  • Save up to 10% on cheap car hire worldwide
  • Exclusive Holiday Autos discount code automatically applied
  • Travel before 31st December 2024 (inclusive)
Show discount codeShow discount code ******vel
Redeem Holiday Autos discount code >>

Expires at 23:59 on Tuesday 31st Dec 2024 · View all Holiday Autos offers

Holiday AutosCar hire finder

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 / mm)  |  Imperial (°F / inches)

Back to top

More about the USA

How hot is it in Seattle in September?

Daytime temperatures usually reach 21°C in Seattle in September, falling to 11°C 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 49mm.

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

Related posts

Popular travel offers

Explore holidays in the sun for less

More holidays

Airport parking

More parking

Airport lounges

More lounges

Top ^