West Yellowstone weather in September 2025

Expect 18°C daytime maximum temperatures in the shade with on average 9 hours of sunshine per day in West Yellowstone in September. Check more long-term weather averages for West Yellowstone in September before you book your next holiday to Montana in 2025/2026.

  • 18°C maximum daytime temperature in September in West Yellowstone18
    18°C max day temperature
  • 9 hours of sunshine per day
  • 8 days with some rainfall in September in West Yellowstone8
    8 days with some rainfall
  • 0°C minimum night-time temperature in September in West Yellowstone0
    0°C min night temperature
  • 12 hours of daylight per day in September in West Yellowstone12
    12 hours of daylight per day
  • No heat & humidity in September in West Yellowstone0
    No heat & humidity
  • 42 mm monthly rainfall in September in West Yellowstone42
    42 mm of monthly rainfall
  • UV (maximum) index 6 (High) in September in West Yellowstone6
    6 (High) UV index

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The September weather guide for Montana (West Yellowstone) 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 West Yellowstone in September?

Daytime temperatures usually reach 18°C in West Yellowstone in September, falling to 0°C at night.

How sunny is it in West Yellowstone in September?

There are normally 9 hours of bright sunshine each day in West Yellowstone in September - that's 69% of daylight hours.

Does it rain in West Yellowstone in September?

There are usually 8 days with some rain in West Yellowstone in September and the average monthly rainfall is 42mm.

West Yellowstone September sunrise & sunset times

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

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Monday, 1st September 2025 05:47 19:00
Monday, 15th September 2025 06:04 18:34
Tuesday, 30th September 2025 06:22 18:06

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