Clinton climate

Clinton Frost Dates and Growing Season

NOAA 1991-2020 normals for Clinton, 3 km from Clinton, elevation 770 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 17 and the first fall freeze around October 21, a growing season of about 187 days.

Median at 36°F
last April 28, first October 10
Median at 32°F
last April 17, first October 21
Median at 28°F
last April 5, first October 31

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 12May 6May 3Apr 30Apr 28Apr 25Apr 21Apr 17Apr 12
32°FMay 2Apr 28Apr 23Apr 19Apr 17Apr 13Apr 9Apr 4Mar 31
28°FApr 22Apr 17Apr 12Apr 9Apr 5Apr 2Mar 31Mar 26Mar 19
24°FApr 12Apr 7Apr 3Mar 31Mar 26Mar 21Mar 17Mar 13Mar 7
20°FApr 2Mar 26Mar 21Mar 17Mar 13Mar 9Mar 6Mar 1Feb 25
16°FMar 20Mar 15Mar 11Mar 8Mar 4Mar 1Feb 27Feb 22Feb 15

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 27Oct 1Oct 5Oct 8Oct 10Oct 13Oct 16Oct 19Oct 23
32°FOct 7Oct 12Oct 16Oct 19Oct 21Oct 24Oct 26Oct 29Nov 1
28°FOct 18Oct 23Oct 25Oct 29Oct 31Nov 1Nov 4Nov 7Nov 12
24°FOct 28Nov 1Nov 3Nov 6Nov 9Nov 12Nov 16Nov 20Nov 27
20°FNov 4Nov 8Nov 12Nov 17Nov 21Nov 25Nov 29Dec 2Dec 8
16°FNov 12Nov 19Nov 24Nov 27Dec 1Dec 4Dec 8Dec 13Dec 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°F187180174170166162157152145
32°F210202195191187183178172164
28°F232223217213208204199194186
24°F253245239233229223218212206
20°F276267261256251246240234225
16°F297288282276271267261255247

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
4,899
Cooling degree days, base 65°F
1,406
Growing degree days, base 40°F
6,568
Growing degree days, base 45°F
5,263
Growing degree days, base 50°F
4,095
Growing degree days, base 55°F
3,062
Growing degree days, base 60°F
2,164

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,08003
February844013
March629474
April32420205
May108106467
June7288730
July0417882
August2377840
September56164559
October28629250
November611263
December95209

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 3 km from Clinton. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00231711 (Clinton). Public domain.