Frost dates in North Dakota

Across North Dakota, the typical last spring frost is around May 12 and the first fall frost around Sep 28. Your own dates depend on where you are in the state; find your county below.

Most of the state's last spring frosts fall between May 6 and May 19, and its first fall frosts between Sep 21 and Oct 3.

These are the dates with a 50% chance of a 32°F frost on or after (spring) or on or before (fall), so plan tender crops a week or two after the spring date and keep row cover handy. For dates at your exact ZIP code, use the zone and frost date lookup; for what to plant when, see the planting guide by frost date.

Hardiness zones in North Dakota: zone 3b, zone 4a, zone 4b

Frost dates by county in North Dakota

CountyLast spring frostFirst fall frostGrowing season
AdamsMay 24Sep 18About 117 days
BarnesMay 11Sep 26About 138 days
BensonMay 12Sep 29About 140 days
BillingsMay 12Sep 28About 139 days
BottineauMay 15Sep 25About 133 days
BowmanMay 16Sep 25About 132 days
BurkeMay 20Sep 19About 122 days
BurleighMay 11Sep 30About 142 days
CassMay 9Oct 1About 145 days
CavalierMay 17Sep 26About 132 days
DickeyMay 7Oct 2About 148 days
DivideMay 17Sep 23About 129 days
DunnMay 20Sep 21About 124 days
EddyMay 12Sep 28About 139 days
EmmonsMay 12Sep 29About 140 days
FosterMay 12Sep 28About 139 days
Golden ValleyMay 16Sep 26About 133 days
Grand ForksMay 11Sep 28About 140 days
GrantMay 19Sep 25About 129 days
GriggsMay 17Sep 23About 129 days
HettingerMay 16Sep 25About 132 days
KidderMay 14Sep 29About 138 days
LaMoureMay 10Sep 28About 141 days
LoganMay 13Sep 28About 138 days
McHenryMay 15Sep 27About 135 days
McIntoshMay 13Sep 27About 137 days
McKenzieMay 11Sep 27About 139 days
McLeanMay 14Sep 28About 137 days
MercerMay 21Sep 20About 122 days
MortonMay 17Sep 24About 130 days
MountrailMay 17Sep 23About 129 days
NelsonMay 11Sep 28About 140 days
OliverMay 11Sep 29About 141 days
PembinaMay 12Sep 30About 141 days
PierceMay 17Sep 23About 129 days
RamseyMay 15Sep 28About 136 days
RansomMay 12Oct 5About 146 days
RenvilleMay 17Sep 23About 129 days
RichlandMay 4Oct 3About 152 days
RoletteMay 20Sep 24About 127 days
SargentMay 7Oct 1About 147 days
SheridanMay 8Oct 1About 146 days
SiouxMay 12Sep 24About 135 days
SlopeMay 16Sep 29About 136 days
StarkMay 20Sep 25About 128 days
SteeleMay 17Sep 24About 130 days
StutsmanMay 11Sep 28About 140 days
TownerMay 18Sep 23About 128 days
TraillMay 2Oct 9About 160 days
WalshMay 4Oct 7About 156 days
WardMay 11Sep 29About 141 days
WellsMay 13Sep 28About 138 days
WilliamsMay 18Sep 21About 126 days

Source: NOAA NCEI U.S. Climate Normals 1991–2020, 50% probability of 32°F, from the weather station nearest each ZIP code; each county shows the middle value across its ZIP codes. Hills, valleys and cities can run a week or more earlier or later.

Frost dates for other states