Clay County climate

Clay County Frost Dates and Growing Season

NOAA 1991-2020 normals for Clendenin, 24 km from Clay County, elevation 700 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Clendenin. 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 21 and the first fall freeze around October 28, a growing season of about 187 days.

Median at 36°F
last May 3, first October 18
Median at 32°F
last April 21, first October 28
Median at 28°F
last April 6, first November 6

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 19May 13May 10May 7May 3Apr 30Apr 26Apr 22Apr 18
32°FMay 11May 3Apr 29Apr 25Apr 21Apr 18Apr 15Apr 11Apr 5
28°FApr 25Apr 17Apr 14Apr 9Apr 6Apr 3Mar 31Mar 28Mar 23
24°FApr 8Apr 3Mar 31Mar 29Mar 26Mar 22Mar 19Mar 15Mar 9
20°FMar 29Mar 24Mar 19Mar 16Mar 13Mar 10Mar 5Feb 28Feb 21
16°FMar 18Mar 13Mar 7Mar 4Mar 1Feb 25Feb 18Feb 11Feb 2

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 7Oct 11Oct 14Oct 16Oct 18Oct 20Oct 23Oct 26Oct 29
32°FOct 15Oct 19Oct 23Oct 25Oct 28Oct 31Nov 1Nov 4Nov 8
28°FOct 26Oct 31Nov 1Nov 4Nov 6Nov 8Nov 11Nov 14Nov 19
24°FNov 4Nov 8Nov 10Nov 13Nov 15Nov 19Nov 22Nov 26Dec 2
20°FNov 12Nov 17Nov 22Nov 26Nov 30Dec 3Dec 7Dec 13Dec 20
16°FNov 26Dec 2Dec 8Dec 13Dec 19Dec 23Dec 27Jan 1Jan 10

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°F184179175171167163159154148
32°F207200196192187183179174167
28°F232225220217213209204200192
24°F260252246241236231227222216
20°F291281274269262257252245237
16°F322309302296290285279271263

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
4,714
Cooling degree days, base 65°F
1,064
Growing degree days, base 40°F
6,208
Growing degree days, base 45°F
4,882
Growing degree days, base 50°F
3,711
Growing degree days, base 55°F
2,683
Growing degree days, base 60°F
1,803

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January98906
February80808
March660154
April32216203
May13071410
June14214649
July0319784
August1291755
September41134543
October28416232
November604154
December860012

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 24 km from Clay County. 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 USC00461723 (Clendenin). Public domain.