Frost dates in Lewistown, MT
The average last spring frost in Lewistown is around May 29 and the first fall frost is around September 16. That gives Lewistown an average growing season of about 110 days.
Last spring frost
| Early (10% chance after) | May 13 |
|---|---|
| Average (50%) | May 29 |
| Late (90%) | June 18 |
First fall frost
| Early (10%) | August 26 |
|---|---|
| Average (50%) | September 16 |
| Late (90% chance before) | October 2 |