Frost dates in Ismay, MT
The average last spring frost in Ismay is around May 20 and the first fall frost is around September 18. That gives Ismay an average growing season of about 121 days.
Last spring frost
| Early (10% chance after) | May 7 |
|---|---|
| Average (50%) | May 20 |
| Late (90%) | June 7 |
First fall frost
| Early (10%) | September 2 |
|---|---|
| Average (50%) | September 18 |
| Late (90% chance before) | October 4 |