Frost dates in Grass Range, MT
The average last spring frost in Grass Range is around May 21 and the first fall frost is around September 20. That gives Grass Range an average growing season of about 122 days.
Last spring frost
| Early (10% chance after) | May 6 |
|---|---|
| Average (50%) | May 21 |
| Late (90%) | June 10 |
First fall frost
| Early (10%) | September 4 |
|---|---|
| Average (50%) | September 20 |
| Late (90% chance before) | October 6 |