Dunn County climate

Dunn County Frost Dates and Growing Season

NOAA 1991-2020 normals for Dunn Ctr 1E, 2.6 km from Dunn County, elevation 2187 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Dunn Ctr 1E. 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 20 and the first fall freeze around September 21, a growing season of about 125 days.

Median at 36°F
last May 29, first September 13
Median at 32°F
last May 20, first September 21
Median at 28°F
last May 9, first September 30

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 17Jun 9Jun 4Jun 1May 29May 27May 25May 21May 17
32°FJun 1May 28May 25May 23May 20May 17May 14May 11May 7
28°FMay 24May 18May 14May 12May 9May 6May 4May 1Apr 27
24°FMay 13May 8May 5May 2Apr 30Apr 27Apr 24Apr 20Apr 16
20°FMay 5May 1Apr 27Apr 23Apr 19Apr 17Apr 14Apr 11Apr 6
16°FApr 25Apr 20Apr 16Apr 13Apr 10Apr 8Apr 5Apr 2Mar 30

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°FAug 27Sep 2Sep 6Sep 10Sep 13Sep 15Sep 19Sep 21Sep 25
32°FSep 7Sep 13Sep 16Sep 19Sep 21Sep 24Sep 27Sep 30Oct 3
28°FSep 16Sep 21Sep 23Sep 27Sep 30Oct 2Oct 5Oct 8Oct 13
24°FSep 22Sep 29Oct 2Oct 5Oct 8Oct 11Oct 13Oct 17Oct 21
20°FOct 2Oct 7Oct 11Oct 14Oct 17Oct 20Oct 23Oct 26Oct 30
16°FOct 10Oct 16Oct 20Oct 24Oct 26Oct 29Nov 1Nov 4Nov 8

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°F123117113108104100958977
32°F143136132128125121116111105
28°F161154151146143139135130124
24°F180174169165160157153149143
20°F197191186183179175170165157
16°F215208204200196193188183176

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
8,965
Cooling degree days, base 65°F
389
Growing degree days, base 40°F
3,782
Growing degree days, base 45°F
2,848
Growing degree days, base 50°F
2,038
Growing degree days, base 55°F
1,351
Growing degree days, base 60°F
796

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,63400
February1,36600
March1,14103
April704028
May37910169
June12151382
July36147577
August47148566
September24131267
October685245
November1,11101
December1,49900

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 2.6 km from Dunn County. 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 USC00322365 (Dunn Ctr 1E). Public domain.