Sun Valley weather in September 2026

Expect daytime maximum temperatures of 20°C in Sun Valley, Idaho in September based on long-term weather averages. There are 9 hours of sunshine per day on average.

  • 20°C maximum daytime temperature in September in Sun Valley20
    20°C max day temperature
  • 9 hours of sunshine per day
  • 8 days with some rainfall in September in Sun Valley8
    8 days with some rainfall
  • 1°C minimum night-time temperature in September in Sun Valley1
    1°C min night temperature
  • 12 hours of daylight per day in September in Sun Valley12
    12 hours of daylight per day
  • No heat & humidity in September in Sun Valley0
    No heat & humidity
  • 26 mm monthly rainfall in September in Sun Valley26
    26 mm of monthly rainfall
  • UV (maximum) index 6 (High) in September in Sun Valley6
    6 (High) UV index

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The September weather guide for Idaho (Sun Valley) 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 Sun Valley in September?

Daytime temperatures usually reach 25°C in Sun Valley in September with no heat and humidity, falling to 8°C at night.

How sunny is it in Sun Valley in September?

There are normally 10 hours of bright sunshine each day in Sun Valley in September - that's 80% of daylight hours.

Does it rain in Sun Valley in September?

There are usually 4 days with some rain in Sun Valley in September and the average monthly rainfall is 19mm.

Sun Valley September sunrise & sunset times

Browse the sunrise and sunset times for Sun Valley in September 2026. Select a month to view Sun Valley sunrise and sunset times for the next 12 months.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Tuesday, 1st September 2026 06:01 19:13
Tuesday, 15th September 2026 06:17 18:47
Wednesday, 30th September 2026 06:34 18:20

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