Frost dates in Thompson Falls, MT
The average last spring frost in Thompson Falls is around May 13 and the first fall frost is around September 27. That gives Thompson Falls an average growing season of about 137 days.
Last spring frost
| Early (10% chance after) | April 27 |
|---|---|
| Average (50%) | May 13 |
| Late (90%) | May 25 |
First fall frost
| Early (10%) | September 12 |
|---|---|
| Average (50%) | September 27 |
| Late (90% chance before) | October 12 |