Rapid City, SD Climate & Monthly Averages
The climate of Rapid City
Seasons are the whole story in Rapid City. The gap between an average July and an average February is 27°C - big day-to-night temperature swings and modest rainfall - which in practice means 86°F (30°C) afternoons at one end of the calendar and 37°F (3°C) at the other.
Climate quick facts
- Hottest month: July - highs near 86°F (30°C)
- Coldest month: February - highs near 37°F (3°C)
- Decade extremes (2015-2024): 105°F (41°C) high · -21°F (-30°C) low
- Wettest month: May (12 rainy days) · Sunniest: July (13.5 h sun/day)
- Climate type: semi-arid
- Annual swing: 27°C between the average warmest and coolest month · day to night: 11°C
- Snow: about 22 days a year
- Months averaging 30°C or hotter: 1
- Average humidity: 57%
Temperatures through the year
July is the warm end of the year, averaging 86°F (30°C) by day and 63°F (17°C) overnight. February is the coolest month, with highs of 37°F (3°C) and lows near 17°F (-8°C). Sunshine averages 9.9 hours a day over the year, peaking in July at 13.5 hours.
Rain, sun and snow
Between the average July and the average February lie 27°C, a wider spread than 91% of the 3496 cities in our dataset. Relative humidity averages 57% across the year, drier than about 89% of the cities we track. Days and nights are about 11°C apart on average - wider than roughly 86% of the cities we track. Precipitation concentrates in May - 3.4 inches (87 mm) on 12 days - and thins out by January. Across the gridded 2015-2024 daily record, the highest daily maximum for this location was 105°F (41°C) and the lowest daily minimum -21°F (-30°C).
How Rapid City compares
- Rapid City averages 49°F (9°C) across the year - cooler than all but 7% of the 3496 cities we track.
Ranked against every city in our dataset, each measured on the same ten-year window.
Monthly climate table
| Month | High | Low | Rain days | Precipitation | Sunshine | Daylight | Wet-day chance | Humidity |
|---|---|---|---|---|---|---|---|---|
| January | 37° | 18° | 4 | 0.5 in | 7.2 h/day | 9.2 h | 12% | 62% |
| February | 37° | 17° | 6 | 0.9 in | 8.2 h/day | 10.4 h | 23% | 58% |
| March | 47° | 26° | 6 | 1.1 in | 9.3 h/day | 11.8 h | 19% | 58% |
| April | 55° | 33° | 9 | 2.4 in | 10.2 h/day | 13.4 h | 31% | 58% |
| May | 65° | 45° | 12 | 3.4 in | 10.9 h/day | 14.7 h | 39% | 61% |
| June | 80° | 58° | 9 | 2.6 in | 13.1 h/day | 15.5 h | 30% | 55% |
| July | 86° | 63° | 8 | 1.6 in | 13.5 h/day | 15.2 h | 26% | 52% |
| August | 83° | 61° | 6 | 1.6 in | 12.6 h/day | 14.0 h | 20% | 52% |
| September | 76° | 54° | 5 | 1.1 in | 10.6 h/day | 12.4 h | 17% | 52% |
| October | 60° | 40° | 6 | 1.5 in | 8.9 h/day | 10.9 h | 19% | 55% |
| November | 48° | 29° | 4 | 0.6 in | 7.7 h/day | 9.6 h | 13% | 55% |
| December | 37° | 20° | 5 | 0.9 in | 6.8 h/day | 8.9 h | 16% | 61% |
Rapid City month by month
Average high and low for each month, with the bar showing where it sits in Rapid City's year (left is the coldest night, right is the warmest afternoon).
January
- Rain
- 4 days
- Sunshine
- 7.2 h
- Daylight
- 9.2 h
- Snow
- 2 days
February
- Rain
- 6 days
- Sunshine
- 8.2 h
- Daylight
- 10.4 h
- Snow
- 4 days
March
- Rain
- 6 days
- Sunshine
- 9.3 h
- Daylight
- 11.8 h
- Snow
- 4 days
April
- Rain
- 9 days
- Sunshine
- 10.2 h
- Daylight
- 13.4 h
- Snow
- 4 days
May
- Rain
- 12 days
- Sunshine
- 10.9 h
- Daylight
- 14.7 h
June
- Rain
- 9 days
- Sunshine
- 13.1 h
- Daylight
- 15.5 h
July
- Rain
- 8 days
- Sunshine
- 13.5 h
- Daylight
- 15.2 h
August
- Rain
- 6 days
- Sunshine
- 12.6 h
- Daylight
- 14.0 h
September
- Rain
- 5 days
- Sunshine
- 10.6 h
- Daylight
- 12.4 h
October
- Rain
- 6 days
- Sunshine
- 8.9 h
- Daylight
- 10.9 h
- Snow
- 2 days
November
- Rain
- 4 days
- Sunshine
- 7.7 h
- Daylight
- 9.6 h
- Snow
- 2 days
December
- Rain
- 5 days
- Sunshine
- 6.8 h
- Daylight
- 8.9 h
- Snow
- 4 days
Warmer places to go, by month: January · February · March · April · May · June · July · August · September · October · November · December
Seasons in Rapid City
Spring (March through May)
Spring in Rapid City is mild, with daytime highs averaging 56°F (13°C) and nights around 35°F (2°C); expect showers on roughly 27 days across the season, plus about 8 snowy days. Daylight is generous - around 10.1 hours of sun a day.
Summer (June through August)
Summer sits firmly in the heat here - highs near 83°F (28°C), nights near 61°F (16°C), and expect showers on roughly 24 days across the season. Daylight is generous - around 13.1 hours of sun a day.
Fall (September through November)
Fall is crisp but comfortable here - highs near 61°F (16°C), nights near 41°F (5°C), and rain comes on about 15 days over the three months, plus about 4 snowy days.
Winter (December through February)
Winter in Rapid City runs to hard cold, with daytime highs averaging 37°F (3°C) and nights around 18°F (-8°C); rain comes on about 15 days over the three months, plus about 10 snowy days. Wind sharpens cold like this considerably; pair the forecast winds with the wind speed converter to judge exposed conditions.
Climate questions, answered
Which months are driest in Rapid City?
How humid does Rapid City get?
How does Rapid City compare to other cities?
Does it freeze in Rapid City?
Best time to visit Rapid City
August to October and May to June is the sweet spot for Rapid City - temperatures sit either side of the peak heat rather than in it. Expect 73°F (23°C) in the afternoon and around 8 days of rain in a typical month of it. For the same question asked the other way round, see where else is warm in August.
Pack for Rapid City with light clothing for the warm months, a heavy insulated coat, hat and gloves for winter and rain gear if you travel around May. July nights average 63°F (17°C), so evenings rarely match the afternoons.
Rapid City temperature records (2015-2024)
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ. Need the precipitation in other units? The mm-to-inches rainfall converter handles it.