Minot climate

Minot Frost Dates and Growing Season

NOAA 1991-2020 normals for Lewiston, 8.4 km from Minot, elevation 180 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lewiston. A median date has an even chance of a later freeze in spring, or an earlier one in fall.

The last spring freeze typically comes around April 25 and the first fall freeze around October 19, a growing season of about 177 days.

Median at 36°F
last May 6, first October 6
Median at 32°F
last April 25, first October 19
Median at 28°F
last April 11, first November 1

Last freeze in spring

The chance of a later freeze than the date shown. At 10 percent, one spring in ten still freezes after the date; planting after the 10 percent date for 32°F is the cautious choice.

Threshold10%20%30%40%50%60%70%80%90%
36°FMay 18May 14May 11May 8May 6May 3May 1Apr 29Apr 25
32°FMay 6May 2Apr 30Apr 28Apr 25Apr 23Apr 20Apr 16Apr 11
28°FApr 24Apr 20Apr 17Apr 13Apr 11Apr 9Apr 6Apr 4Apr 2
24°FApr 13Apr 8Apr 5Apr 4Apr 3Apr 1Mar 30Mar 26Mar 20
20°FApr 5Apr 2Mar 31Mar 29Mar 26Mar 23Mar 20Mar 17Mar 14
16°FApr 1Mar 29Mar 25Mar 22Mar 20Mar 17Mar 14Mar 12Mar 8

First freeze in fall

The chance of an earlier freeze than the date shown. At 10 percent, one fall in ten freezes before the date.

Threshold10%20%30%40%50%60%70%80%90%
36°FSep 27Oct 1Oct 2Oct 4Oct 6Oct 9Oct 11Oct 15Oct 21
32°FOct 5Oct 9Oct 13Oct 16Oct 19Oct 23Oct 26Oct 30Nov 3
28°FOct 17Oct 23Oct 26Oct 29Nov 1Nov 3Nov 6Nov 10Nov 15
24°FNov 1Nov 5Nov 9Nov 11Nov 14Nov 16Nov 19Nov 23Nov 28
20°FNov 12Nov 16Nov 19Nov 22Nov 25Nov 28Nov 30Dec 3Dec 8
16°FNov 20Nov 25Nov 29Dec 1Dec 3Dec 5Dec 8Dec 12Dec 17

Growing season length

Days between the last spring and first fall freeze at each threshold, with the chance of a season at least that long.

Threshold10%20%30%40%50%60%70%80%90%
36°F170164160156153149146142136
32°F198190185181177173169165159
28°F221213209205202198194190184
24°F243236231227224221217213208
20°F261256252248244240237232225
16°F276271266262259255252246241

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
100% of years
32°F or colder
100% of years
28°F or colder
100% of years
24°F or colder
100% of years
20°F or colder
100% of years
16°F or colder
100% of years

Degree days

A degree day is one degree of the daily mean temperature beyond a base, for one day. Heating degree days count cold (the fuel a house burns), cooling degree days heat, growing degree days the warmth a crop needs; each crop has its own base.

Heating degree days, base 65°F
7,271
Cooling degree days, base 65°F
485
Growing degree days, base 40°F
4,297
Growing degree days, base 45°F
3,268
Growing degree days, base 50°F
2,366
Growing degree days, base 55°F
1,596
Growing degree days, base 60°F
968

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,39500
February1,18600
March1,04001
April635027
May30111198
June8079449
July11192646
August15164614
September15239341
October485183
November80407
December1,16900

What this means

NOAA computes these from the daily lows at the station over 1991-2020, fitting the dates of each year's last and first freeze to a distribution, so a date can be stated at any level of risk. 36°F is a frost risk for tender plants on a clear, calm night, since the ground cools below the air above it; 32°F is a freeze; 28°F is a hard freeze that kills most annuals.

The station is 8.4 km from Minot. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00174566 (Lewiston). Public domain.