Houston County climate

Houston County Frost Dates and Growing Season

NOAA 1991-2020 normals for Tennessee Ridge, 7.7 km from Houston County, elevation 722 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Tennessee Ridge. 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 7 and the first fall freeze around November 3, a growing season of about 211 days.

Median at 36°F
last April 19, first October 24
Median at 32°F
last April 7, first November 3
Median at 28°F
last March 28, first November 14

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 3Apr 30Apr 26Apr 22Apr 19Apr 15Apr 12Apr 9Apr 4
32°FApr 24Apr 19Apr 14Apr 10Apr 7Apr 4Apr 1Mar 29Mar 24
28°FApr 18Apr 8Apr 3Mar 31Mar 28Mar 24Mar 20Mar 16Mar 8
24°FApr 7Mar 29Mar 23Mar 19Mar 15Mar 11Mar 6Mar 3Feb 25
20°FMar 22Mar 17Mar 12Mar 8Mar 4Feb 28Feb 23Feb 16Feb 7
16°FMar 13Mar 6Mar 1Feb 25Feb 19Feb 13Feb 7Feb 1Jan 24

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 12Oct 16Oct 19Oct 22Oct 24Oct 26Oct 29Nov 1Nov 5
32°FOct 21Oct 26Oct 29Nov 1Nov 3Nov 5Nov 8Nov 12Nov 18
28°FNov 1Nov 4Nov 7Nov 10Nov 14Nov 17Nov 21Nov 26Dec 1
24°FNov 7Nov 12Nov 17Nov 21Nov 25Nov 29Dec 1Dec 6Dec 12
20°FNov 16Nov 23Nov 28Dec 1Dec 5Dec 9Dec 15Dec 21Dec 28
16°FNov 27Dec 3Dec 8Dec 12Dec 19Dec 24Dec 29Jan 3Jan 14

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°F209202197193190185181175168
32°F234224219215211206202196188
28°F257249243237232227222217207
24°F281272266261255249244235226
20°F305296289283277272265258248
16°F333323314307303297290282270

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
98% 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
3,920
Cooling degree days, base 65°F
1,543
Growing degree days, base 40°F
7,269
Growing degree days, base 45°F
5,832
Growing degree days, base 50°F
4,538
Growing degree days, base 55°F
3,392
Growing degree days, base 60°F
2,393

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January886018
February702130
March5157108
April23837280
May69134531
June4296742
July0415880
August1393857
September27207630
October19950333
November500498
December780029

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 7.7 km from Houston 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 USC00408916 (Tennessee Ridge). Public domain.