Henry County climate

Henry County Frost Dates and Growing Season

NOAA 1991-2020 normals for Paris 2 Se, 5 km from Henry County, elevation 443 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Paris 2 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 April 7 and the first fall freeze around October 31, a growing season of about 206 days.

Median at 36°F
last April 19, first October 22
Median at 32°F
last April 7, first October 31
Median at 28°F
last March 28, first November 8

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 4Apr 30Apr 26Apr 22Apr 19Apr 16Apr 12Apr 9Apr 4
32°FApr 22Apr 17Apr 13Apr 10Apr 7Apr 5Apr 2Mar 30Mar 23
28°FApr 11Apr 7Apr 3Mar 31Mar 28Mar 23Mar 19Mar 15Mar 8
24°FApr 1Mar 26Mar 21Mar 16Mar 13Mar 9Mar 5Feb 28Feb 22
20°FMar 20Mar 14Mar 8Mar 4Feb 28Feb 25Feb 19Feb 14Feb 4
16°FMar 10Mar 2Feb 27Feb 21Feb 16Feb 10Feb 5Jan 31Jan 22

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 9Oct 14Oct 17Oct 20Oct 22Oct 24Oct 26Oct 28Nov 1
32°FOct 19Oct 23Oct 25Oct 28Oct 31Nov 1Nov 3Nov 6Nov 12
28°FOct 30Nov 1Nov 4Nov 6Nov 8Nov 11Nov 14Nov 19Nov 27
24°FNov 5Nov 8Nov 12Nov 16Nov 19Nov 23Nov 27Dec 1Dec 8
20°FNov 11Nov 17Nov 22Nov 27Dec 1Dec 4Dec 8Dec 16Dec 26
16°FNov 25Dec 1Dec 7Dec 13Dec 22Dec 27Jan 1Jan 7Jan 17

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°F203197193188184180176171165
32°F226220214210206202198193187
28°F254244238233228223219213206
24°F278270263258252246241235227
20°F308297290285279273265259246
16°F337327319312306300292284274

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
99% 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
3,978
Cooling degree days, base 65°F
1,471
Growing degree days, base 40°F
7,159
Growing degree days, base 45°F
5,729
Growing degree days, base 50°F
4,443
Growing degree days, base 55°F
3,305
Growing degree days, base 60°F
2,311

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January892020
February696130
March5207112
April24132274
May68123520
June4292738
July0401866
August1379843
September28196618
October21737307
November521287
December789029

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 5 km from Henry 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 USC00406977 (Paris 2 Se). Public domain.