Great Falls weather in May 2025

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

  • 18°C maximum daytime temperature in May in Great Falls18
    18°C max day temperature
  • 9 hours of sunshine per day
  • 12 days with some rainfall in May in Great Falls12
    12 days with some rainfall
  • 5°C minimum night-time temperature in May in Great Falls5
    5°C min night temperature
  • 15 hours of daylight per day in May in Great Falls15
    15 hours of daylight per day
  • No heat & humidity in May in Great Falls0
    No heat & humidity
  • 63 mm monthly rainfall in May in Great Falls63
    63 mm of monthly rainfall
  • UV (maximum) index 6 (High) in May in Great Falls6
    6 (High) UV index

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The May weather guide for Montana (Great Falls) 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 Great Falls in May?

Daytime temperatures usually reach 18°C in Great Falls in May, falling to 5°C at night.

How sunny is it in Great Falls in May?

There are normally 9 hours of bright sunshine each day in Great Falls in May - that's 61% of daylight hours.

Does it rain in Great Falls in May?

There are usually 12 days with some rain in Great Falls in May and the average monthly rainfall is 63mm.

Great Falls May sunrise & sunset times

Browse the sunrise and sunset times for Great Falls in May 2025. Select a month to view Great Falls sunrise and sunset times for the next 12 months.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Thursday, 1st May 2025 05:08 19:38
Friday, 16th May 2025 04:46 19:58
Saturday, 31st May 2025 04:32 20:14

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