Rapid City Temperatures: Averages by Month





The numbers here tell you how hot and cold the weather usually is in Rapid City, South Dakota during each month of the year.

The average high and low temperatures are listed below monthly and annually for the city, in both degrees Fahrenheit and Celsius.

Maximums and minimums are only part of the temperature picture. To fill in the rest, there's information on how many days a month get above or below a given temperature.

To find out how often it rises over 70, 80 or 90 °F each month in Rapid City, scroll down farther. There are also monthly and yearly counts of days with cold weather.

The first set of high and low temperatures are averages for 2010 to 2019. Everything else here is based on 1991 to 2020 weather.

10-year temperature averages for Rapid City, 2010 to 2019
High °F Low °F   High °C Low °C
36 13 January 2 -11
38 14 February 3 -10
48 23 March 9 -5
57 31 April 14 0
67 42 May 19 5
78 52 June 25 11
86 59 July 30 15
85 56 August 30 13
76 46 September 25 8
60 34 October 16 1
47 22 November 9 -6
37 14 December 3 -10
60 34 Year 15 1
30-year temperature averages for Rapid City, 1991 to 2020
High °F Low °F   High °C Low °C
37 16 January 3 -9
39 18 February 4 -8
47 25 March 8 -4
56 34 April 13 1
66 45 May 19 7
76 54 June 24 12
84 62 July 29 17
84 60 August 29 15
73 50 September 23 10
59 38 October 15 3
46 28 November 8 -3
37 18 December 3 -8
59 37 Year 15 3

Days of Hot Weather in Rapid City

Most summer days at Rapid City have highs in the 80s Fahrenheit. Normally 32 days a year reach 90 degrees, and an average of five days annually spike to 100 °F (38 °C) or more.

Number of days in Rapid City of at least 70, 80 or 90 °F
  70 °F
21 °C
80 °F
27 °C
90 °F
32 °C
January 0 0 0
February 1 0 0
March 3 0 0
April 6 2 0
May 13 4 1
June 25 14 4
July 30 25 12
August 30 25 11
September 22 13 4
October 9 3 0
November 2 0 0
December 0 0 0
Year 140 86 32

How Often Rapid City Has Cold Temperatures

Rapid City typically has 174 nights below freezing a year, that show up from September to May. Eighteen of the coldest winter nights drop down to 0 °F (-18 °C) or lower.

For an average of 43 days annually the thermometer never rises above freezing. Days that chilly can occur from October to April.

Days per month on average in Rapid City when the minimum temperature drops to 20, 10 or 0 °F or below
  0 °F
-18 °C
10 °F
-12 °C
20 °F
-8 °C
January 6 12 21
February 5 10 18
March 2 4 10
April 0 1 3
May 0 0 0
June 0 0 0
July 0 0 0
August 0 0 0
September 0 0 0
October 0 1 2
November 1 4 12
December 4 10 21
Year 18 41 88
References

Jay Lawrimore, Ron Ray, Scott Applequist, Bryant Korzeniewski, Matthew Menne. 2016. Global Summary of the Month and Year, Version 1.0. NOAA National Centers for Environmental Information.

NOAA National Centers for Environmental Information (NCEI). Climate Normals.

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