Frost dates in Rock Springs, WY
The average last spring frost in Rock Springs is around May 20 and the first fall frost is around September 22. That gives Rock Springs an average growing season of about 125 days.
Last spring frost
| Early (10% chance after) | May 4 |
|---|---|
| Average (50%) | May 20 |
| Late (90%) | June 9 |
First fall frost
| Early (10%) | September 11 |
|---|---|
| Average (50%) | September 22 |
| Late (90% chance before) | October 8 |