Frost dates in Spearfish, SD
The average last spring frost in Spearfish is around May 12 and the first fall frost is around October 1. That gives Spearfish an average growing season of about 142 days.
Last spring frost
| Early (10% chance after) | April 23 |
|---|---|
| Average (50%) | May 12 |
| Late (90%) | May 27 |
First fall frost
| Early (10%) | September 12 |
|---|---|
| Average (50%) | October 1 |
| Late (90% chance before) | October 14 |