Wheeler County climate

Wheeler County Frost Dates and Growing Season

NOAA 1991-2020 normals for Shamrock #2, 20.8 km from Wheeler County, elevation 2360 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Shamrock #2. 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 9 and the first fall freeze around October 30, a growing season of about 202 days.

Median at 36°F
last April 20, first October 22
Median at 32°F
last April 9, first October 30
Median at 28°F
last March 31, first November 6

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

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 7Oct 13Oct 16Oct 19Oct 22Oct 24Oct 27Oct 29Nov 3
32°FOct 17Oct 21Oct 25Oct 27Oct 30Nov 1Nov 4Nov 7Nov 11
28°FOct 22Oct 28Nov 1Nov 3Nov 6Nov 9Nov 12Nov 16Nov 22
24°FOct 30Nov 4Nov 8Nov 12Nov 15Nov 19Nov 23Nov 27Dec 3
20°FNov 6Nov 12Nov 18Nov 22Nov 25Nov 29Dec 4Dec 8Dec 14
16°FNov 20Nov 26Dec 1Dec 5Dec 10Dec 14Dec 20Dec 26Jan 5

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°F202196190186182179175170164
32°F224216211207202198193187181
28°F246239232227222218212206199
24°F269261254250244239234227217
20°F292284278272267262256250241
16°F325314305299293288280273263

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
3,972
Cooling degree days, base 65°F
1,698
Growing degree days, base 40°F
7,370
Growing degree days, base 45°F
5,924
Growing degree days, base 50°F
4,634
Growing degree days, base 55°F
3,503
Growing degree days, base 60°F
2,528

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January865010
February683025
March4985114
April25326258
May78132522
June4340786
July1489953
August1444908
September27222646
October21238315
November528283
December823014

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 20.8 km from Wheeler 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 USC00418236 (Shamrock #2). Public domain.