Frost dates in Napoleon, ND
The average last spring frost in Napoleon is around May 20 and the first fall frost is around September 19. That gives Napoleon an average growing season of about 122 days.
Last spring frost
| Early (10% chance after) | May 3 |
|---|---|
| Average (50%) | May 20 |
| Late (90%) | June 8 |
First fall frost
| Early (10%) | September 1 |
|---|---|
| Average (50%) | September 19 |
| Late (90% chance before) | October 6 |