Clay County climate

Clay County Frost Dates and Growing Season

NOAA 1991-2020 normals for State Univ, 20.8 km from Clay County, elevation 185 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for State Univ. 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 March 23 and the first fall freeze around November 8, a growing season of about 233 days.

Median at 36°F
last April 5, first October 31
Median at 32°F
last March 23, first November 8
Median at 28°F
last March 7, first November 22

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°FApr 23Apr 18Apr 13Apr 9Apr 5Apr 2Mar 30Mar 24Mar 16
32°FApr 13Apr 5Apr 1Mar 28Mar 23Mar 18Mar 15Mar 7Feb 28
28°FMar 30Mar 22Mar 17Mar 12Mar 7Mar 4Feb 28Feb 23Feb 14
24°FMar 17Mar 9Mar 4Feb 28Feb 23Feb 16Feb 9Feb 2Jan 25
20°FMar 6Feb 26Feb 14Feb 7Feb 2Jan 30Jan 24Jan 17Jan 6
16°FFeb 28Feb 8Feb 1Jan 30Jan 26Jan 21Jan 14Jan 7Dec 31

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°FOct 17Oct 23Oct 26Oct 29Oct 31Nov 1Nov 4Nov 8Nov 14
32°FOct 27Oct 31Nov 2Nov 5Nov 8Nov 12Nov 16Nov 23Dec 1
28°FNov 4Nov 9Nov 14Nov 18Nov 22Nov 28Dec 2Dec 6Dec 17
24°FNov 15Nov 21Nov 28Dec 1Dec 6Dec 12Dec 22Dec 31Jan 7
20°FNov 26Dec 6Dec 13Dec 24Dec 30Jan 2Jan 8Jan 14Jan 24
16°FDec 13Dec 26Jan 1Jan 4Jan 8Jan 12Jan 17Jan 23Feb 2

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°F233224218213209204200194188
32°F261251243238233229223216207
28°F292281273266260254248241232
24°F326315306300292285278269256
20°F360346338333326318309301287
16°F365365365365356347339333317

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
92% of years
16°F or colder
67% 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
2,699
Cooling degree days, base 65°F
2,207
Growing degree days, base 40°F
8,797
Growing degree days, base 45°F
7,181
Growing degree days, base 50°F
5,710
Growing degree days, base 55°F
4,386
Growing degree days, base 60°F
3,219

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January663153
February496376
March32820215
April12872402
May21230674
June0417867
July0525990
August0502967
September7323766
October11696453
November36014171
December580475

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 20.8 km from Clay 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 USC00228374 (State Univ). Public domain.