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Frost dates for Grand Forks, North Dakota

In a typical year, Grand Forks’s last spring frost lands around May 10 and the first fall frost around Oct 1, a growing season of about 144 days. These are odds drawn from 30-year NOAA climate normals, not a promise. USDA zone 4a.

Right now the typical frost season has arrived; planting waits for spring.

Last spring frost and first fall frost odds for Grand Forks, North Dakota
OddsLast spring frostFirst fall frost
10 percentApr 28Sep 20
50 percentMay 10Oct 1
90 percentMay 24Oct 15

A 10 percent year is an early year, a 90 percent year a late one. Frost-sensitive planting usually waits for the 90 percent side of the last-frost band.

Soil in Grand Forks is typically around 43°F at 4 inches this time of year, estimated from the last two weeks of normal air temperatures.

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Common questions

When is the last frost in Grand Forks, North Dakota?

Grand Forks’s last spring frost falls around May 10 in a typical year. One year in ten it is done by April 28, and one year in ten frost holds on until May 24. Frost-sensitive planting usually waits for the late side of that band.

When is the first fall frost in Grand Forks?

The first fall frost arrives around October 1 in a typical year, as early as September 20 in an early year and as late as October 15 in a late one.

How long is the growing season in Grand Forks?

About 144 days, counted between the typical last spring frost and the typical first fall frost.

What USDA zone is Grand Forks in?

Grand Forks is in USDA hardiness zone 4a under the 2023 USDA Plant Hardiness Zone Map.

Dates come from 30-year NOAA climate normals for the nearest reporting station. They describe odds, not a forecast.

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