Coosa County climate

Coosa County Frost Dates and Growing Season

NOAA 1991-2020 normals for Rockford 3 Ese, 9.9 km from Coosa County, elevation 600 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Rockford 3 Ese. 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 25 and the first fall freeze around November 11, a growing season of about 230 days.

Median at 36°F
last April 7, first November 1
Median at 32°F
last March 25, first November 11
Median at 28°F
last March 11, first November 24

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 25Apr 19Apr 14Apr 11Apr 7Apr 4Mar 31Mar 27Mar 20
32°FApr 13Apr 6Apr 3Mar 30Mar 25Mar 21Mar 17Mar 12Mar 4
28°FApr 1Mar 24Mar 20Mar 16Mar 11Mar 6Mar 1Feb 24Feb 15
24°FMar 18Mar 10Mar 4Feb 28Feb 22Feb 16Feb 8Feb 1Jan 23
20°FMar 3Feb 21Feb 13Feb 5Feb 1Jan 29Jan 23Jan 16Jan 5
16°FFeb 16Feb 5Feb 1Jan 28Jan 23Jan 18Jan 12Jan 6Dec 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 19Oct 23Oct 26Oct 29Nov 1Nov 3Nov 5Nov 8Nov 14
32°FOct 28Nov 1Nov 5Nov 8Nov 11Nov 14Nov 18Nov 22Dec 1
28°FNov 7Nov 12Nov 16Nov 20Nov 24Nov 28Dec 1Dec 6Dec 15
24°FNov 17Nov 23Nov 30Dec 2Dec 6Dec 13Dec 21Dec 30Jan 6
20°FDec 2Dec 8Dec 20Dec 27Jan 1Jan 6Jan 11Jan 18Jan 29
16°FDec 15Dec 27Jan 2Jan 5Jan 11Jan 15Jan 20Jan 28Feb 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°F232222217212207203197193187
32°F258248242236230225220213205
28°F288279271264258252246239230
24°F328315305299292284277269259
20°F362348338334326317308301290
16°F365365365364354344337329318

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
92% of years
16°F or colder
66% 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
2,611
Cooling degree days, base 65°F
1,724
Growing degree days, base 40°F
8,352
Growing degree days, base 45°F
6,709
Growing degree days, base 50°F
5,212
Growing degree days, base 55°F
3,876
Growing degree days, base 60°F
2,709

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January633149
February461276
March31113213
April12645376
May28172609
June1326775
July0432897
August0401866
September5259703
October12064415
November3648155
December564377

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 9.9 km from Coosa 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 USC00017020 (Rockford 3 Ese). Public domain.