Calhoun Falls climate

Calhoun Falls Frost Dates and Growing Season

NOAA 1991-2020 normals for Calhoun Falls, 0.7 km from Calhoun Falls, elevation 530 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Calhoun Falls. 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 27 and the first fall freeze around November 7, a growing season of about 226 days.

Median at 36°F
last April 6, first October 30
Median at 32°F
last March 27, first November 7
Median at 28°F
last March 13, first November 22

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 16Apr 12Apr 9Apr 6Apr 3Mar 31Mar 28Mar 21
32°FApr 11Apr 5Apr 1Mar 29Mar 27Mar 23Mar 19Mar 16Mar 8
28°FMar 30Mar 26Mar 21Mar 17Mar 13Mar 7Mar 2Feb 26Feb 16
24°FMar 18Mar 11Mar 5Mar 1Feb 25Feb 18Feb 11Feb 3Jan 25
20°FMar 7Feb 28Feb 19Feb 10Feb 4Jan 31Jan 25Jan 17Jan 4
16°FFeb 26Feb 9Feb 3Jan 30Jan 25Jan 19Jan 15Jan 8Dec 31

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 22Oct 25Oct 27Oct 30Nov 1Nov 3Nov 6Nov 11
32°FOct 26Oct 31Nov 2Nov 5Nov 7Nov 10Nov 14Nov 18Nov 24
28°FNov 5Nov 10Nov 15Nov 18Nov 22Nov 26Dec 1Dec 6Dec 15
24°FNov 17Nov 25Dec 1Dec 4Dec 8Dec 16Dec 25Jan 1Jan 9
20°FDec 1Dec 10Dec 20Dec 27Jan 1Jan 5Jan 11Jan 18Feb 2
16°FDec 21Dec 29Jan 2Jan 7Jan 13Jan 17Jan 23Jan 29Feb 10

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°F225219213210206202199194187
32°F250242236231226222217212205
28°F284274266259253248243236227
24°F325313303296289282275267256
20°F363350339332325317307299287
16°F365365365365358349341332316

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
92% of years
16°F or colder
58% 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
2,914
Cooling degree days, base 65°F
1,880
Growing degree days, base 40°F
8,232
Growing degree days, base 45°F
6,627
Growing degree days, base 50°F
5,189
Growing degree days, base 55°F
3,916
Growing degree days, base 60°F
2,812

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January673037
February523154
March3779166
April15749350
May35179609
June2370817
July0494959
August0448913
September10263703
October13660395
November3947133
December607151

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 0.7 km from Calhoun Falls. 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 USC00381277 (Calhoun Falls). Public domain.