Calhoun County climate

Calhoun County Frost Dates and Growing Season

NOAA 1991-2020 normals for Elsberry 1 S, 10.1 km from Calhoun County, elevation 475 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Elsberry 1 S. 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 April 20 and the first fall freeze around October 20, a growing season of about 181 days.

Median at 36°F
last April 30, first October 10
Median at 32°F
last April 20, first October 20
Median at 28°F
last April 6, first October 29

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°FMay 14May 9May 5May 2Apr 30Apr 27Apr 24Apr 21Apr 16
32°FMay 5Apr 30Apr 27Apr 23Apr 20Apr 17Apr 13Apr 9Apr 6
28°FApr 24Apr 18Apr 13Apr 9Apr 6Apr 3Apr 1Mar 29Mar 23
24°FApr 12Apr 6Apr 2Mar 31Mar 28Mar 24Mar 20Mar 15Mar 10
20°FApr 1Mar 28Mar 23Mar 19Mar 16Mar 12Mar 9Mar 5Feb 28
16°FMar 22Mar 17Mar 13Mar 10Mar 7Mar 4Mar 1Feb 26Feb 19

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°FSep 26Sep 30Oct 5Oct 7Oct 10Oct 12Oct 15Oct 18Oct 22
32°FOct 6Oct 11Oct 14Oct 17Oct 20Oct 22Oct 24Oct 28Oct 31
28°FOct 17Oct 21Oct 24Oct 26Oct 29Oct 31Nov 2Nov 6Nov 11
24°FOct 28Nov 1Nov 3Nov 5Nov 8Nov 11Nov 14Nov 18Nov 24
20°FNov 5Nov 9Nov 13Nov 15Nov 19Nov 23Nov 27Dec 1Dec 6
16°FNov 12Nov 17Nov 22Nov 27Dec 1Dec 4Dec 8Dec 12Dec 19

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°F180174170166162158154149143
32°F201195189185181177173167161
28°F224217212208205202198192184
24°F249241235231227223218213206
20°F272263257252248243237232225
16°F292284277272267262257251242

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
100% of years
16°F or colder
100% 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
5,140
Cooling degree days, base 65°F
1,159
Growing degree days, base 40°F
6,204
Growing degree days, base 45°F
4,930
Growing degree days, base 50°F
3,788
Growing degree days, base 55°F
2,777
Growing degree days, base 60°F
1,895

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,12503
February88809
March663364
April32519204
May11590444
June10243682
July1354818
August4300761
September65128515
October30622227
November645154
December99507

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 10.1 km from Calhoun 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 USC00232591 (Elsberry 1 S). Public domain.