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Frost dates for Bismarck, North Dakota

In a typical year, Bismarck’s last spring frost lands around May 10 and the first fall frost around Sep 30, a growing season of about 143 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 Bismarck, North Dakota
OddsLast spring frostFirst fall frost
10 percentApr 30Sep 16
50 percentMay 10Sep 30
90 percentMay 23Oct 13

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 Bismarck 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 Bismarck, North Dakota?

Bismarck’s last spring frost falls around May 10 in a typical year. One year in ten it is done by April 30, and one year in ten frost holds on until May 23. Frost-sensitive planting usually waits for the late side of that band.

When is the first fall frost in Bismarck?

The first fall frost arrives around September 30 in a typical year, as early as September 16 in an early year and as late as October 13 in a late one.

How long is the growing season in Bismarck?

About 143 days, counted between the typical last spring frost and the typical first fall frost.

What USDA zone is Bismarck in?

Bismarck 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.

Nearby cities

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