Frost dates in Rapid City, SD
The average last spring frost in Rapid City is around May 4 and the first fall frost is around October 9. That gives Rapid City an average growing season of about 158 days.
Last spring frost
| Early (10% chance after) | April 18 |
|---|---|
| Average (50%) | May 4 |
| Late (90%) | May 16 |
First fall frost
| Early (10%) | September 28 |
|---|---|
| Average (50%) | October 9 |
| Late (90% chance before) | October 27 |