Frost dates in Plains, MT
The average last spring frost in Plains is around June 17 and the first fall frost is around September 6. That gives Plains an average growing season of about 81 days.
Last spring frost
| Early (10% chance after) | May 20 |
|---|---|
| Average (50%) | June 17 |
| Late (90%) | July 18 |
First fall frost
| Early (10%) | August 18 |
|---|---|
| Average (50%) | September 6 |
| Late (90% chance before) | September 28 |