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Friday Harbor weather in September 2025
Expect 18°C daytime maximum temperatures in the shade with on average 7 hours of sunshine per day in Friday Harbor in September. Check more long-term weather averages for Friday Harbor in September before you book your next holiday to Washington State in 2025/2026.
- 18°C max day temperature
18 - 7 hours of sunshine per day
- 9 days with some rainfall
9 - 10°C min night temperature
10 - 13 hours of daylight per day
13 - No heat & humidity
0 - 36 mm of monthly rainfall
36 - 5 (Moderate) UV index
5 - 12°C sea temperature
12
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Recommended for Washington State
The September weather guide for Washington State (Friday Harbor) 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)
More about the USA
How hot is it in Friday Harbor in September?
Daytime temperatures usually reach 18°C in Friday Harbor in September, falling to 10°C at night.
How sunny is it in Friday Harbor in September?
There are normally 7 hours of bright sunshine each day in Friday Harbor in September - that's 53% of daylight hours.
How warm is the sea around Friday Harbor in September?
The average sea temperature around Friday Harbor in September is 12°C.
Does it rain in Friday Harbor in September?
There are usually 9 days with some rain in Friday Harbor in September and the average monthly rainfall is 36mm.
Friday Harbor September sunrise & sunset times
Browse the sunrise and sunset times for Friday Harbor in September 2025. Select a month to view Friday Harbor sunrise and sunset times for the next 12 months.
JanFebMarAprMayJunJulAugSepOctNovDec
| Date | Sunrise times | Sunset times |
|---|---|---|
| Monday, 1st September 2025 | 05:30 | 18:53 |
| Monday, 15th September 2025 | 05:49 | 18:24 |
| Tuesday, 30th September 2025 | 06:11 | 17:52 |
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