Howell County climate

Howell County Frost Dates and Growing Season

NOAA 1991-2020 normals for W Plains, 5.4 km from Howell County, elevation 1105 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for W Plains. 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 16 and the first fall freeze around October 21, a growing season of about 189 days.

Median at 36°F
last April 27, first October 13
Median at 32°F
last April 16, first October 21
Median at 28°F
last April 4, 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 7May 3Apr 30Apr 27Apr 24Apr 21Apr 17Apr 12
32°FMay 3Apr 27Apr 23Apr 19Apr 16Apr 13Apr 9Apr 6Mar 31
28°FApr 21Apr 14Apr 10Apr 7Apr 4Apr 1Mar 29Mar 24Mar 18
24°FApr 8Apr 2Mar 30Mar 26Mar 22Mar 18Mar 15Mar 10Mar 3
20°FMar 28Mar 21Mar 17Mar 14Mar 10Mar 7Mar 3Feb 27Feb 22
16°FMar 17Mar 11Mar 7Mar 3Feb 28Feb 23Feb 19Feb 13Feb 3

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 1Oct 4Oct 7Oct 10Oct 13Oct 15Oct 18Oct 21Oct 24
32°FOct 8Oct 13Oct 16Oct 19Oct 21Oct 24Oct 27Oct 30Nov 2
28°FOct 17Oct 22Oct 26Oct 29Oct 31Nov 2Nov 6Nov 9Nov 16
24°FOct 30Nov 2Nov 5Nov 9Nov 11Nov 15Nov 21Nov 26Dec 1
20°FNov 7Nov 11Nov 15Nov 20Nov 24Nov 28Dec 1Dec 7Dec 13
16°FNov 14Nov 22Nov 28Dec 1Dec 6Dec 11Dec 16Dec 21Dec 30

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°F186180175171167164160156150
32°F209202198193189185180175166
28°F234225220216211207202197189
24°F260249244239234230225219211
20°F284276269263258252248242234
16°F312301294287281276270263252

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
4,617
Cooling degree days, base 65°F
1,213
Growing degree days, base 40°F
6,436
Growing degree days, base 45°F
5,099
Growing degree days, base 50°F
3,909
Growing degree days, base 55°F
2,864
Growing degree days, base 60°F
1,964

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January99007
February769014
March606372
April29517217
May10978436
June11239678
July1382846
August3327789
September50143544
October28923236
November594260
December90009

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 5.4 km from Howell 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 USC00238880 (W Plains). Public domain.