Clinton climate

Clinton Frost Dates and Growing Season

NOAA 1991-2020 normals for Clinton, 1.9 km from Clinton, elevation 1570 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Clinton. 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 13 and the first fall freeze around October 28, a growing season of about 197 days.

Median at 36°F
last April 22, first October 20
Median at 32°F
last April 13, first October 28
Median at 28°F
last April 1, first November 5

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 5May 1Apr 28Apr 25Apr 22Apr 19Apr 16Apr 14Apr 9
32°FApr 27Apr 22Apr 19Apr 16Apr 13Apr 10Apr 7Apr 4Mar 31
28°FApr 18Apr 12Apr 7Apr 4Apr 1Mar 29Mar 24Mar 18Mar 11
24°FApr 5Mar 31Mar 27Mar 22Mar 17Mar 12Mar 8Mar 3Feb 26
20°FMar 25Mar 17Mar 12Mar 8Mar 4Feb 28Feb 25Feb 20Feb 11
16°FMar 14Mar 8Mar 4Feb 28Feb 24Feb 19Feb 13Feb 6Jan 27

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 6Oct 11Oct 15Oct 17Oct 20Oct 21Oct 24Oct 26Oct 30
32°FOct 14Oct 19Oct 22Oct 25Oct 28Oct 30Nov 2Nov 5Nov 9
28°FOct 20Oct 25Oct 30Nov 2Nov 5Nov 8Nov 11Nov 14Nov 19
24°FOct 27Nov 3Nov 7Nov 11Nov 14Nov 17Nov 21Nov 24Nov 29
20°FNov 5Nov 13Nov 17Nov 21Nov 24Nov 28Dec 1Dec 5Dec 12
16°FNov 19Nov 25Nov 30Dec 3Dec 7Dec 12Dec 18Dec 23Jan 1

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°F197191186182179174171168161
32°F217210205201197192188184177
28°F244235229224219215209204195
24°F266259251246241235230224217
20°F290282275269265260254248237
16°F320308301295289283277270260

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
3,622
Cooling degree days, base 65°F
2,019
Growing degree days, base 40°F
7,919
Growing degree days, base 45°F
6,438
Growing degree days, base 50°F
5,115
Growing degree days, base 55°F
3,943
Growing degree days, base 60°F
2,909

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January83408
February646127
March4338147
April19533305
May44169591
June1400849
July05501,015
August0512976
September18287718
October16557371
November486396
December800013

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 1.9 km from Clinton. 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 USC00341909 (Clinton). Public domain.