Crookston climate

Crookston Frost Dates and Growing Season

NOAA 1991-2020 normals for Crookston Nw Exp Stn, 5 km from Crookston, elevation 891 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Crookston Nw Exp Stn. 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 May 11 and the first fall freeze around September 27, a growing season of about 138 days.

Median at 36°F
last May 22, first September 17
Median at 32°F
last May 11, first September 27
Median at 28°F
last May 1, first October 7

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°FJun 3May 30May 28May 25May 22May 19May 16May 12May 7
32°FMay 25May 20May 16May 13May 11May 8May 5May 2Apr 28
28°FMay 16May 11May 7May 4May 1Apr 29Apr 27Apr 23Apr 18
24°FMay 7May 2Apr 29Apr 26Apr 22Apr 19Apr 16Apr 12Apr 7
20°FApr 28Apr 22Apr 18Apr 15Apr 12Apr 9Apr 6Apr 4Apr 1
16°FApr 19Apr 14Apr 10Apr 7Apr 5Apr 3Apr 1Mar 28Mar 21

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 3Sep 9Sep 12Sep 15Sep 17Sep 20Sep 22Sep 25Sep 28
32°FSep 14Sep 18Sep 22Sep 24Sep 27Sep 30Oct 3Oct 6Oct 10
28°FSep 23Sep 27Oct 1Oct 4Oct 7Oct 10Oct 14Oct 18Oct 23
24°FOct 1Oct 6Oct 10Oct 14Oct 18Oct 22Oct 25Oct 30Nov 3
20°FOct 11Oct 17Oct 22Oct 27Oct 30Nov 1Nov 3Nov 7Nov 12
16°FOct 22Oct 28Oct 31Nov 2Nov 5Nov 8Nov 11Nov 14Nov 18

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°F13612912612111811411010599
32°F157151146142138134130126119
28°F179172166161157153150145137
24°F199191187183178174170164157
20°F218212206202198194190184176
16°F233227223218214210206201194

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
9,464
Cooling degree days, base 65°F
422
Growing degree days, base 40°F
3,875
Growing degree days, base 45°F
2,961
Growing degree days, base 50°F
2,152
Growing degree days, base 55°F
1,447
Growing degree days, base 60°F
863

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,82600
February1,53700
March1,25903
April729031
May34121208
June8489456
July29155591
August46120539
September23834272
October663251
November1,12501
December1,58700

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 5 km from Crookston. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00211891 (Crookston Nw Exp Stn). Public domain.