Madison County climate

Madison County Frost Dates and Growing Season

NOAA 1991-2020 normals for Madison, 6.9 km from Madison County, elevation 120 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Madison. 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 5 and the first fall freeze around November 29, a growing season of about 273 days.

Median at 36°F
last March 18, first November 17
Median at 32°F
last March 5, first November 29
Median at 28°F
last February 14, first December 15

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 5Mar 30Mar 26Mar 22Mar 18Mar 14Mar 9Mar 3Feb 24
32°FMar 23Mar 18Mar 13Mar 9Mar 5Feb 28Feb 22Feb 14Feb 3
28°FMar 15Mar 5Feb 28Feb 20Feb 14Feb 7Jan 31Jan 25Jan 10
24°FFeb 28Feb 16Feb 7Feb 2Jan 28Jan 21Jan 13Jan 5Dec 26
20°FFeb 14Feb 6Jan 31Jan 25Jan 19Jan 12Jan 6Dec 31Dec 21
16°F–––––––––

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°FNov 1Nov 5Nov 10Nov 15Nov 17Nov 21Nov 25Nov 30Dec 6
32°FNov 10Nov 17Nov 21Nov 25Nov 29Dec 3Dec 7Dec 15Dec 28
28°FNov 21Nov 28Dec 3Dec 9Dec 15Dec 24Jan 1Jan 7Jan 19
24°FDec 3Dec 12Dec 20Dec 29Jan 3Jan 9Jan 16Jan 26Feb 6
20°FDec 12Dec 23Dec 29Jan 3Jan 9Jan 14Jan 20Jan 30Feb 7
16°F–––––––––

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°F275265257251245239234228219
32°F309297287279273266260253243
28°F343330322314305297289280267
24°F365365355344336330321311301
20°F365365365365365365357341328
16°F365365365365365365365365365

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
96% of years
24°F or colder
77% of years
20°F or colder
36% of years
16°F or colder
8% 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
1,510
Cooling degree days, base 65°F
2,506
Growing degree days, base 40°F
10,149
Growing degree days, base 45°F
8,386
Growing degree days, base 50°F
6,701
Growing degree days, base 55°F
5,138
Growing degree days, base 60°F
3,728

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January4238145
February28412190
March16841351
April54114511
May6288747
June0438888
July0502967
August0499964
September1374823
October40173599
November18842321
December34714195

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 6.9 km from Madison 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 USC00085275 (Madison). Public domain.