Clay County climate

Clay County Frost Dates and Growing Season

NOAA 1991-2020 normals for Flora, 8.5 km from Clay County, elevation 481 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Flora. 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 9 and the first fall freeze around October 24, a growing season of about 198 days.

Median at 36°F
last April 21, first October 15
Median at 32°F
last April 9, first October 24
Median at 28°F
last March 31, first November 3

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 6May 1Apr 27Apr 23Apr 21Apr 18Apr 14Apr 11Apr 8
32°FApr 23Apr 19Apr 15Apr 11Apr 9Apr 7Apr 4Apr 2Mar 29
28°FApr 14Apr 9Apr 5Apr 2Mar 31Mar 28Mar 25Mar 21Mar 14
24°FApr 4Mar 31Mar 27Mar 24Mar 20Mar 16Mar 12Mar 9Mar 1
20°FMar 24Mar 20Mar 15Mar 12Mar 8Mar 5Mar 1Feb 26Feb 18
16°FMar 17Mar 11Mar 6Mar 3Feb 28Feb 24Feb 20Feb 13Feb 5

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 1Oct 6Oct 9Oct 12Oct 15Oct 18Oct 20Oct 22Oct 26
32°FOct 11Oct 16Oct 20Oct 22Oct 24Oct 27Oct 29Nov 1Nov 6
28°FOct 22Oct 26Oct 29Nov 1Nov 3Nov 6Nov 9Nov 13Nov 19
24°FNov 1Nov 5Nov 8Nov 12Nov 15Nov 18Nov 22Nov 26Dec 1
20°FNov 8Nov 13Nov 18Nov 22Nov 26Nov 29Dec 3Dec 7Dec 14
16°FNov 16Nov 25Nov 29Dec 2Dec 6Dec 10Dec 16Dec 21Dec 27

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°F194188183179175170166161154
32°F217210205202198194190185177
28°F240233227222218214210205198
24°F264255250245240236232226219
20°F288279272267262258253246239
16°F309300293287280276271264255

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
4,933
Cooling degree days, base 65°F
1,337
Growing degree days, base 40°F
6,471
Growing degree days, base 45°F
5,173
Growing degree days, base 50°F
4,018
Growing degree days, base 55°F
2,995
Growing degree days, base 60°F
2,101

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,08504
February855011
March662363
April31221217
May101114481
June7296739
July0385849
August2330793
September51156556
October29031245
November625151
December94408

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 8.5 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 USC00113106 (Flora). Public domain.