Frost dates in Portal, ND
The average last spring frost in Portal is around May 20 and the first fall frost is around September 19. That gives Portal an average growing season of about 122 days.
Last spring frost
| Early (10% chance after) | May 2 |
|---|---|
| Average (50%) | May 20 |
| Late (90%) | May 30 |
First fall frost
| Early (10%) | September 10 |
|---|---|
| Average (50%) | September 19 |
| Late (90% chance before) | October 5 |