White County climate

White County Frost Dates and Growing Season

NOAA 1991-2020 normals for Carmi 3, 1.6 km from White County, elevation 335 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Carmi 3. 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 15 and the first fall freeze around October 19, a growing season of about 183 days.

Median at 36°F
last April 28, first October 8
Median at 32°F
last April 15, first October 19
Median at 28°F
last April 3, first October 28

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 14May 8May 4May 1Apr 28Apr 25Apr 21Apr 17Apr 13
32°FMay 2Apr 27Apr 23Apr 19Apr 15Apr 13Apr 10Apr 7Apr 2
28°FApr 19Apr 13Apr 9Apr 6Apr 3Apr 1Mar 30Mar 26Mar 19
24°FApr 7Apr 3Mar 31Mar 28Mar 24Mar 21Mar 17Mar 13Mar 6
20°FMar 28Mar 24Mar 20Mar 17Mar 13Mar 9Mar 5Mar 1Feb 24
16°FMar 19Mar 14Mar 10Mar 6Mar 2Feb 28Feb 24Feb 19Feb 11

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 23Sep 30Oct 3Oct 6Oct 8Oct 11Oct 13Oct 17Oct 20
32°FOct 4Oct 8Oct 12Oct 16Oct 19Oct 20Oct 23Oct 26Oct 29
28°FOct 12Oct 19Oct 23Oct 25Oct 28Oct 30Nov 1Nov 4Nov 9
24°FOct 25Oct 29Nov 1Nov 3Nov 5Nov 8Nov 12Nov 17Nov 24
20°FNov 3Nov 6Nov 10Nov 14Nov 18Nov 22Nov 27Dec 1Dec 6
16°FNov 9Nov 16Nov 21Nov 27Dec 1Dec 4Dec 9Dec 16Dec 24

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°F181175169165162158154149142
32°F202196191187183179174169161
28°F226220214209205201197192185
24°F249242236231227222218213207
20°F275267260254249245240235228
16°F301292284279273267262255247

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
4,857
Cooling degree days, base 65°F
1,245
Growing degree days, base 40°F
6,395
Growing degree days, base 45°F
5,086
Growing degree days, base 50°F
3,921
Growing degree days, base 55°F
2,896
Growing degree days, base 60°F
2,001

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,04906
February848010
March644259
April30520215
May101106472
June8274717
July1362826
August3309772
September53146544
October28924239
November627153
December930010

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 1.6 km from White County. 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 USC00111302 (Carmi 3). Public domain.