Meriwether County climate

Meriwether County Frost Dates and Growing Season

NOAA 1991-2020 normals for Atlanta, 37.6 km from Meriwether County, elevation 858 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Atlanta. 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 26 and the first fall freeze around November 6, a growing season of about 226 days.

Median at 36°F
last April 8, first October 29
Median at 32°F
last March 26, first November 6
Median at 28°F
last March 9, first November 20

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 23Apr 18Apr 15Apr 12Apr 8Apr 5Apr 1Mar 28Mar 22
32°FApr 13Apr 7Apr 2Mar 30Mar 26Mar 22Mar 18Mar 13Mar 4
28°FMar 31Mar 24Mar 19Mar 14Mar 9Mar 4Feb 28Feb 23Feb 13
24°FMar 16Mar 9Mar 2Feb 25Feb 19Feb 12Feb 6Jan 31Jan 22
20°FMar 6Feb 23Feb 12Feb 5Jan 31Jan 27Jan 21Jan 14Jan 5
16°FFeb 14Feb 5Jan 31Jan 28Jan 22Jan 18Jan 13Jan 6Dec 30

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 17Oct 21Oct 23Oct 26Oct 29Oct 31Nov 2Nov 5Nov 10
32°FOct 25Oct 30Nov 1Nov 4Nov 6Nov 9Nov 13Nov 18Nov 24
28°FNov 4Nov 8Nov 12Nov 16Nov 20Nov 24Nov 29Dec 3Dec 12
24°FNov 16Nov 23Nov 28Dec 2Dec 6Dec 12Dec 23Jan 1Jan 7
20°FDec 1Dec 8Dec 15Dec 24Dec 30Jan 3Jan 9Jan 16Jan 26
16°FDec 13Dec 24Jan 1Jan 4Jan 10Jan 15Jan 20Jan 26Feb 1

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°F224217211207203199195190183
32°F254242235231226221216211204
28°F288277269262255250245238229
24°F330318308301293287279271259
20°F365352344336330324315306294
16°F365365365365355346337330319

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
99% of years
20°F or colder
90% of years
16°F or colder
62% 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
2,587
Cooling degree days, base 65°F
1,945
Growing degree days, base 40°F
8,584
Growing degree days, base 45°F
6,933
Growing degree days, base 50°F
5,434
Growing degree days, base 55°F
4,095
Growing degree days, base 60°F
2,928

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January624158
February459380
March31213209
April12951376
May25193632
June1377826
July0488953
August0459924
September7280723
October11673426
November3617151
December553275

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 37.6 km from Meriwether 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 USW00053819 (Atlanta). Public domain.