Plains climate

Plains Frost Dates and Growing Season

NOAA 1991-2020 normals for Plains Sw Ga Exp Stn, 2.5 km from Plains, elevation 500 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Plains Sw Ga Exp Stn. 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 March 15 and the first fall freeze around November 17, a growing season of about 249 days.

Median at 36°F
last March 31, first November 6
Median at 32°F
last March 15, first November 17
Median at 28°F
last February 28, first December 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°FApr 15Apr 10Apr 6Apr 2Mar 31Mar 27Mar 23Mar 18Mar 10
32°FApr 2Mar 28Mar 23Mar 20Mar 15Mar 11Mar 6Mar 1Feb 22
28°FMar 21Mar 14Mar 8Mar 4Feb 28Feb 24Feb 19Feb 11Feb 1
24°FMar 10Mar 1Feb 25Feb 16Feb 10Feb 2Jan 30Jan 23Jan 10
20°FFeb 26Feb 12Feb 4Jan 31Jan 27Jan 22Jan 15Jan 8Dec 30
16°FFeb 10Feb 2Jan 31Jan 26Jan 20Jan 16Jan 11Jan 5Dec 29

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 24Oct 29Nov 1Nov 3Nov 6Nov 9Nov 13Nov 17Nov 23
32°FNov 1Nov 6Nov 10Nov 14Nov 17Nov 21Nov 25Dec 1Dec 9
28°FNov 11Nov 17Nov 22Nov 27Dec 1Dec 5Dec 12Dec 24Jan 3
24°FNov 23Dec 1Dec 7Dec 14Dec 23Dec 31Jan 5Jan 12Jan 23
20°FDec 6Dec 16Dec 27Jan 1Jan 6Jan 10Jan 17Jan 25Feb 3
16°FDec 14Dec 30Jan 4Jan 9Jan 14Jan 18Jan 24Jan 30Feb 4

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°F249240232227222217212206199
32°F278268261255249243238231223
28°F315304294288281275267260249
24°F349336329321312305298289277
20°F365365358348340334328320306
16°F365365365365365364351340329

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
97% of years
20°F or colder
76% of years
16°F or colder
39% 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
2,231
Cooling degree days, base 65°F
2,063
Growing degree days, base 40°F
9,032
Growing degree days, base 45°F
7,338
Growing degree days, base 50°F
5,771
Growing degree days, base 55°F
4,356
Growing degree days, base 60°F
3,114

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January560280
February4153102
March27221249
April10865410
May16225674
June0392842
July0482947
August0451916
September4303748
October88100481
November29117211
December4784111

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 2.5 km from Plains. 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 USC00097087 (Plains Sw Ga Exp Stn). Public domain.