Clinton climate

Clinton Frost Dates and Growing Season

NOAA 1991-2020 normals for Clinton 5 Se, 6.7 km from Clinton, elevation 200 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Clinton 5 Se. 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 13 and the first fall freeze around November 17, a growing season of about 251 days.

Median at 36°F
last March 29, first November 6
Median at 32°F
last March 13, first November 17
Median at 28°F
last February 27, first December 1

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 16Apr 9Apr 5Apr 1Mar 29Mar 24Mar 18Mar 13Mar 5
32°FApr 4Mar 28Mar 22Mar 17Mar 13Mar 8Mar 3Feb 26Feb 18
28°FMar 21Mar 14Mar 8Mar 3Feb 27Feb 21Feb 14Feb 5Jan 28
24°FMar 11Mar 1Feb 22Feb 13Feb 4Jan 31Jan 25Jan 18Jan 5
20°FFeb 27Feb 13Feb 2Jan 31Jan 24Jan 17Jan 11Jan 3Dec 26
16°FFeb 8Jan 31Jan 27Jan 20Jan 15Jan 11Jan 6Jan 1Dec 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 24Oct 29Nov 1Nov 3Nov 6Nov 9Nov 13Nov 17Nov 24
32°FNov 1Nov 6Nov 9Nov 13Nov 17Nov 20Nov 25Dec 1Dec 6
28°FNov 10Nov 16Nov 21Nov 27Dec 1Dec 5Dec 11Dec 21Jan 2
24°FNov 23Dec 2Dec 9Dec 18Dec 27Jan 1Jan 6Jan 13Jan 29
20°FDec 9Dec 21Dec 29Jan 2Jan 6Jan 10Jan 16Jan 25Feb 4
16°FDec 25Dec 31Jan 2Jan 5Jan 8Jan 13Jan 18Jan 26Feb 3

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°F253243235228223219214208200
32°F283272264257251244238231222
28°F320307298291283275268258247
24°F359343335329321314305294281
20°F365365365364354346337331316
16°F365365365365365365365359343

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
93% of years
20°F or colder
61% of years
16°F or colder
25% 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
1,957
Cooling degree days, base 65°F
2,222
Growing degree days, base 40°F
9,449
Growing degree days, base 45°F
7,729
Growing degree days, base 50°F
6,115
Growing degree days, base 55°F
4,647
Growing degree days, base 60°F
3,342

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January5055104
February35411148
March22533298
April8790456
May12233687
June0400850
July0473938
August0470935
September2343790
October72130525
November26324245
December43812140

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 6.7 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 USC00161899 (Clinton 5 Se). Public domain.