Anderson County climate

Anderson County Frost Dates and Growing Season

NOAA 1991-2020 normals for Garnett 1 E, 9.8 km from Anderson County, elevation 998 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Garnett 1 E. 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 17 and the first fall freeze around October 22, a growing season of about 189 days.

Median at 36°F
last April 28, first October 14
Median at 32°F
last April 17, first October 22
Median at 28°F
last April 6, first November 1

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 10May 6May 3Apr 30Apr 28Apr 25Apr 21Apr 17Apr 12
32°FMay 1Apr 27Apr 24Apr 20Apr 17Apr 14Apr 10Apr 6Apr 1
28°FApr 22Apr 17Apr 12Apr 9Apr 6Apr 3Mar 31Mar 27Mar 20
24°FApr 13Apr 6Apr 3Mar 31Mar 27Mar 22Mar 19Mar 13Mar 6
20°FApr 3Mar 29Mar 23Mar 18Mar 14Mar 10Mar 6Mar 2Feb 25
16°FMar 24Mar 16Mar 11Mar 8Mar 4Mar 1Feb 27Feb 22Feb 16

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°FSep 29Oct 4Oct 8Oct 11Oct 14Oct 17Oct 19Oct 22Oct 26
32°FOct 7Oct 13Oct 17Oct 20Oct 22Oct 25Oct 28Oct 31Nov 4
28°FOct 17Oct 22Oct 26Oct 29Nov 1Nov 3Nov 5Nov 9Nov 13
24°FOct 28Nov 1Nov 3Nov 5Nov 9Nov 12Nov 14Nov 19Nov 27
20°FNov 3Nov 7Nov 11Nov 14Nov 17Nov 22Nov 26Dec 1Dec 7
16°FNov 10Nov 15Nov 21Nov 25Nov 29Dec 2Dec 6Dec 13Dec 19

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°F187181175171167164159154145
32°F209202197193189184180175167
28°F231223217212207203199194186
24°F251243238232228223218211202
20°F274265259253247242236230222
16°F295286279274270263257251242

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
4,935
Cooling degree days, base 65°F
1,391
Growing degree days, base 40°F
6,544
Growing degree days, base 45°F
5,245
Growing degree days, base 50°F
4,079
Growing degree days, base 55°F
3,046
Growing degree days, base 60°F
2,150

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,08203
February856011
March634370
April33414196
May11198457
June8279721
July1422887
August2373837
September55171567
October27529261
November618262
December96108

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 9.8 km from Anderson 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 USC00143008 (Garnett 1 E). Public domain.