Oglethorpe climate

Oglethorpe Frost Dates and Growing Season

NOAA 1991-2020 normals for Americus, 34.1 km from Oglethorpe, elevation 397 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Americus. 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 20 and the first fall freeze around November 14, a growing season of about 238 days.

Median at 36°F
last April 2, first November 4
Median at 32°F
last March 20, first November 14
Median at 28°F
last March 4, first November 28

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 21Apr 15Apr 10Apr 6Apr 2Mar 31Mar 26Mar 21Mar 15
32°FApr 7Mar 31Mar 27Mar 23Mar 20Mar 16Mar 11Mar 5Feb 26
28°FMar 24Mar 18Mar 14Mar 9Mar 4Feb 27Feb 21Feb 14Feb 3
24°FMar 13Mar 5Feb 27Feb 19Feb 13Feb 5Jan 31Jan 24Jan 12
20°FFeb 28Feb 16Feb 7Feb 2Jan 29Jan 22Jan 16Jan 9Jan 1
16°FFeb 16Feb 5Feb 1Jan 28Jan 21Jan 15Jan 10Jan 4Dec 28

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 23Oct 27Oct 30Nov 1Nov 4Nov 6Nov 9Nov 13Nov 18
32°FNov 1Nov 4Nov 7Nov 10Nov 14Nov 17Nov 20Nov 26Dec 3
28°FNov 7Nov 13Nov 18Nov 23Nov 28Dec 1Dec 6Dec 13Dec 25
24°FNov 20Nov 28Dec 3Dec 8Dec 16Dec 25Jan 1Jan 6Jan 15
20°FDec 5Dec 15Dec 25Dec 31Jan 3Jan 9Jan 14Jan 22Feb 1
16°FDec 17Dec 29Jan 2Jan 7Jan 13Jan 17Jan 24Jan 29Feb 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°F239230225218215211206200193
32°F268257250244238234228223216
28°F305291283276269263256249240
24°F343331320313306298292282270
20°F365365355346339333325314303
16°F365365365365365364351340328

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
98% of years
20°F or colder
80% of years
16°F or colder
41% 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
2,289
Cooling degree days, base 65°F
2,036
Growing degree days, base 40°F
8,947
Growing degree days, base 45°F
7,253
Growing degree days, base 50°F
5,696
Growing degree days, base 55°F
4,307
Growing degree days, base 60°F
3,078

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January563172
February417399
March28115235
April11657394
May15214665
June0381831
July0477942
August0459924
September3312759
October8499484
November31416199
December497293

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 34.1 km from Oglethorpe. 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 USC00090253 (Americus). Public domain.