Rapid City weather in August 2026

Expect daytime maximum temperatures of 29°C in Rapid City, South Dakota in August based on long-term weather averages. There are 10 hours of sunshine per day on average with typically 48 mm of rainfall in the month.

  • 29°C maximum daytime temperature in August in Rapid City29
    29°C max day temperature
  • 10 hours of sunshine per day
  • 8 days with some rainfall in August in Rapid City8
    8 days with some rainfall
  • 13°C minimum night-time temperature in August in Rapid City13
    13°C min night temperature
  • 14 hours of daylight per day in August in Rapid City14
    14 hours of daylight per day
  • Moderate heat & humidity in August in Rapid CityM
    Moderate heat & humidity
  • 48 mm monthly rainfall in August in Rapid City48
    48 mm of monthly rainfall
  • UV (maximum) index 8 (Very High) in August in Rapid City8
    8 (Very High) UV index

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The August weather guide for South Dakota (Rapid City) 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 Rapid City in August?

Daytime temperatures usually reach 29°C in Rapid City in August with moderate heat and humidity, falling to 13°C at night.

How sunny is it in Rapid City in August?

There are normally 10 hours of bright sunshine each day in Rapid City in August - that's 74% of daylight hours.

Does it rain in Rapid City in August?

There are usually 8 days with some rain in Rapid City in August and the average monthly rainfall is 48mm.

Rapid City August sunrise & sunset times

Browse the sunrise and sunset times for Rapid City in August 2026. Select a month to view Rapid City sunrise and sunset times for the next 12 months.

JanFebMarAprMayJunJulAugSepOctNovDec

Date Sunrise times Sunset times
Saturday, 1st August 2026 04:41 19:17
Sunday, 16th August 2026 04:58 18:56
Monday, 31st August 2026 05:15 18:30

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