Frost dates in Casper, WY
The average last spring frost in Casper is around May 13 and the first fall frost is around October 5. That gives Casper an average growing season of about 145 days.
Last spring frost
| Early (10% chance after) | May 4 |
|---|---|
| Average (50%) | May 13 |
| Late (90%) | May 28 |
First fall frost
| Early (10%) | September 20 |
|---|---|
| Average (50%) | October 5 |
| Late (90% chance before) | October 15 |