Average Last Spring Frost / Freeze Date Probabilities

A question we are often asked in early spring is "By what date does my town typically get its last frost or freeze?" The charts and maps below will help answer that question for several locations across western South Dakota.

The charts below shows what chance the last frost (36º F) or freeze (32º F or below) will occur by a specific date. For example, in 90% of past years, the temperature at Rapid City last reached 32º F by May 24th. In half of the past years, Rapid City last reached 28ºF by April 28th.

The regional maps farther down show the average date of the first freeze (32º F) and hard freeze (28º F).

Rapid City	36º F	32º F	28º F	24º F
90%	June 12	May 24	May 14	May 2
50%	May 21	May 9	April 28	April 17
10%	May 8	April 20	April 13	April 5

Lead	36º F	32º F	28º F	24º F
90%	June 22	June 13	May 23	May 15
50%	June 4	May 23	May 9	April 29
10%	May 19	May 9	April 23	April 14

Custer	36º F	32º F	28º F	24º F
90%	June 29	June 26	June 13	May 29
50%	June 18	June 4	May 22	May 9
10%	May 26	May 16	May 4	April 21

Faith	36º F	32º F	28º F	24º F
90%	June 6	May 27	May 11	May 1
50%	May 18	May 9	April 28	April 16
10%	May 5	April 24	April 11	April 3

Camp Crook	36º F	32º F	28º F	24º F
90%	June 17	June 8	May 26	May 16
50%	June 4	May 22	May 11	April 29
10%	May 18	May 9	April 29	April 15

Oelrichs	36º F	32º F	28º F	24º F
90%	June 10	June 3	May 19	May 12
50%	May 25	May 15	May 3	April 26
10%	May 15	May 4	April 18	April 5

Winner	36º F	32º F	28º F	24º F
90%	May 30	May 23	May 13	May 3
50%	May 16	May 7	April 22	April 15
10%	May 2	April 21	April 9	March 30

Regional Maps: Median Date for last freeze (32º F) and hard freeze (28º F)

A special thanks to the Midwestern Regional Climate Center for these maps.