Rapid City, SD Climate & Monthly Averages
Rapid City has a semi-arid climate. July is the hottest month, averaging 86° by day; February is the coldest at 37°.
Winter sets the pace in 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.
July
86° by day 63° at nightFebruary
37° by day 17° at nightThe cold-weather pattern in numbers
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.
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).
More climate facts for Rapid City
- 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%
From snow season to the warmest stretch 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.
The coldest and warmest values in the dataset
Derived from ERA5 reanalysis data, 2015–2024. Official station records may differ. Need another precipitation unit? Use the rainfall converter.
Planning around winter in Rapid City
The easier weather window
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.
Cold-weather packing
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.
Monthly highs, lows and seasonal change
| 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% |
The route from winter to summer, month by month
Each card shows the average high and low. The bar places that month between Rapid City's coldest night and 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
Looking for warmer alternatives? Browse warm places by month, or compare Rapid City's coolest part of the year: February, January, December.
Where Rapid City sits among other climates
- Rapid City averages 49°F (9°C) across the year - cooler than all but 7% of the 3496 cities we track.
These comparisons use the same ten-year window for every city in the dataset.