Anderson County climate

Anderson County Frost Dates and Growing Season

NOAA 1991-2020 normals for Frankfort Capital City AP, 21.5 km from Anderson County, elevation 804 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Frankfort Capital City AP. 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 15 and the first fall freeze around October 24, a growing season of about 192 days.

Median at 36°F
last April 26, first October 15
Median at 32°F
last April 15, first October 24
Median at 28°F
last April 3, first November 4

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 13May 7May 3Apr 30Apr 26Apr 23Apr 20Apr 15Apr 12
32°FMay 5Apr 27Apr 22Apr 19Apr 15Apr 12Apr 8Apr 5Mar 31
28°FApr 22Apr 15Apr 9Apr 5Apr 3Mar 31Mar 28Mar 23Mar 16
24°FApr 6Apr 1Mar 29Mar 25Mar 22Mar 18Mar 15Mar 9Mar 2
20°FMar 26Mar 21Mar 16Mar 13Mar 9Mar 5Mar 1Feb 24Feb 16
16°FMar 17Mar 11Mar 7Mar 3Feb 27Feb 22Feb 16Feb 10Feb 3

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 3Oct 7Oct 11Oct 13Oct 15Oct 17Oct 20Oct 22Oct 26
32°FOct 13Oct 17Oct 20Oct 22Oct 24Oct 26Oct 29Nov 1Nov 5
28°FOct 23Oct 26Oct 30Nov 1Nov 4Nov 6Nov 9Nov 13Nov 17
24°FNov 1Nov 5Nov 8Nov 12Nov 15Nov 18Nov 22Nov 28Dec 3
20°FNov 9Nov 15Nov 19Nov 23Nov 28Dec 1Dec 4Dec 10Dec 18
16°FNov 18Nov 27Dec 1Dec 4Dec 9Dec 15Dec 21Dec 25Dec 31

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°F189183179174171167162157151
32°F211204200196192188183177169
28°F238229224219215211206200193
24°F267257251244240235230224217
20°F292284278271265260254247238
16°F318307300294289282277269259

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
4,386
Cooling degree days, base 65°F
1,332
Growing degree days, base 40°F
6,745
Growing degree days, base 45°F
5,370
Growing degree days, base 50°F
4,141
Growing degree days, base 55°F
3,060
Growing degree days, base 60°F
2,122

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January958016
February762122
March586582
April27726242
May92109484
June7269713
July0378843
August1345809
September40166576
October26131265
November567267
December836023

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 21.5 km from Anderson 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 USW00053841 (Frankfort Capital City AP). Public domain.