North Dakota planting zones & frost dates

Last updated October 19, 2026

The 2 North Dakota cities on this site fall in zone 4a. Last spring frost dates range from May 11 in Fargo to May 14 in Bismarck.

City	Zone	Last frost	First frost	Population
Fargo	4a	May 11	Sep 28	136,285
Bismarck	4a	May 14	Sep 25	77,772

Frost dates are 30%-risk dates from the nearest suitable NOAA station. Population: Census Vintage 2024 estimates.