Keystone weather in May 2025

Expect 19°C daytime maximum temperatures in the shade with on average 9 hours of sunshine per day in Keystone in May. Check more long-term weather averages for Keystone in May before you book your next holiday to South Dakota in 2025/2026.

  • 19°C maximum daytime temperature in May in Keystone19
    19°C max day temperature
  • 9 hours of sunshine per day
  • 12 days with some rainfall in May in Keystone12
    12 days with some rainfall
  • 5°C minimum night-time temperature in May in Keystone5
    5°C min night temperature
  • 15 hours of daylight per day in May in Keystone15
    15 hours of daylight per day
  • No heat & humidity in May in Keystone0
    No heat & humidity
  • 77 mm monthly rainfall in May in Keystone77
    77 mm of monthly rainfall
  • UV (maximum) index 7 (High) in May in Keystone7
    7 (High) UV index

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The May weather guide for South Dakota (Keystone) 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 Keystone in May?

Daytime temperatures usually reach 19°C in Keystone in May, falling to 5°C at night.

How sunny is it in Keystone in May?

There are normally 9 hours of bright sunshine each day in Keystone in May - that's 59% of daylight hours.

Does it rain in Keystone in May?

There are usually 12 days with some rain in Keystone in May and the average monthly rainfall is 77mm.

Keystone May sunrise & sunset times

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

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Thursday, 1st May 2025 04:45 18:57
Friday, 16th May 2025 04:26 19:14
Saturday, 31st May 2025 04:15 19:29

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