Madison County climate

Madison County Frost Dates and Growing Season

NOAA 1991-2020 normals for Morrisville 6 Sw, 9.2 km from Madison County, elevation 1681 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Morrisville 6 Sw. 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 May 6 and the first fall freeze around October 9, a growing season of about 156 days.

Median at 36°F
last May 19, first October 1
Median at 32°F
last May 6, first October 9
Median at 28°F
last April 26, first October 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°FJun 1May 28May 25May 22May 19May 15May 12May 8May 3
32°FMay 21May 17May 12May 9May 6May 3Apr 30Apr 28Apr 25
28°FMay 9May 4May 1Apr 29Apr 26Apr 23Apr 21Apr 18Apr 13
24°FApr 27Apr 23Apr 20Apr 18Apr 15Apr 12Apr 9Apr 7Apr 4
20°FApr 18Apr 14Apr 10Apr 7Apr 5Apr 3Apr 2Mar 31Mar 26
16°FApr 10Apr 5Apr 3Apr 1Mar 31Mar 29Mar 26Mar 22Mar 18

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 17Sep 23Sep 25Sep 28Oct 1Oct 2Oct 5Oct 7Oct 11
32°FSep 28Oct 1Oct 4Oct 6Oct 9Oct 13Oct 16Oct 19Oct 25
28°FOct 5Oct 10Oct 15Oct 19Oct 22Oct 25Oct 29Nov 1Nov 6
24°FOct 16Oct 23Oct 27Oct 31Nov 2Nov 5Nov 8Nov 12Nov 17
20°FOct 30Nov 3Nov 8Nov 11Nov 13Nov 16Nov 19Nov 23Nov 29
16°FNov 9Nov 14Nov 17Nov 20Nov 23Nov 27Dec 1Dec 3Dec 9

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°F152146141137133128125120113
32°F173168163159156152148143137
28°F198192187182178174170165157
24°F219213209205202197193189181
20°F240233227224221217213210202
16°F255250245242238234230226219

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
7,805
Cooling degree days, base 65°F
284
Growing degree days, base 40°F
3,890
Growing degree days, base 45°F
2,894
Growing degree days, base 50°F
2,030
Growing degree days, base 55°F
1,296
Growing degree days, base 60°F
700

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,41200
February1,22400
March1,11806
April689241
May34214193
June11553391
July36107536
August5082498
September19925289
October560267
November85509
December1,20701

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 9.2 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 USC00305512 (Morrisville 6 Sw). Public domain.