Greer County climate

Greer County Frost Dates and Growing Season

NOAA 1991-2020 normals for Mangum, 7.4 km from Greer County, elevation 1595 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mangum. 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 8 and the first fall freeze around November 2, a growing season of about 207 days.

Median at 36°F
last April 18, first October 25
Median at 32°F
last April 8, first November 2
Median at 28°F
last March 27, first November 10

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 1Apr 28Apr 24Apr 21Apr 18Apr 15Apr 12Apr 8Apr 2
32°FApr 24Apr 19Apr 15Apr 11Apr 8Apr 4Apr 1Mar 28Mar 21
28°FApr 13Apr 7Apr 3Mar 31Mar 27Mar 23Mar 18Mar 12Mar 4
24°FApr 2Mar 27Mar 22Mar 17Mar 12Mar 8Mar 4Feb 28Feb 22
20°FMar 20Mar 14Mar 9Mar 4Mar 1Feb 25Feb 21Feb 15Feb 7
16°FMar 9Mar 2Feb 27Feb 22Feb 16Feb 9Feb 3Jan 29Jan 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 13Oct 18Oct 20Oct 23Oct 25Oct 28Oct 31Nov 3Nov 7
32°FOct 19Oct 23Oct 27Oct 30Nov 2Nov 4Nov 7Nov 10Nov 16
28°FOct 25Oct 30Nov 4Nov 7Nov 10Nov 12Nov 16Nov 20Nov 26
24°FNov 1Nov 6Nov 11Nov 15Nov 19Nov 22Nov 25Nov 30Dec 5
20°FNov 8Nov 16Nov 21Nov 24Nov 28Dec 2Dec 6Dec 11Dec 19
16°FNov 19Nov 25Dec 1Dec 6Dec 12Dec 18Dec 23Dec 30Jan 9

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°F209202197192188184181176170
32°F229221216212207203198193186
28°F253244237232227222217212204
24°F274266261255249243237231221
20°F300290284277272267261254244
16°F334322313306300292285278268

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
3,577
Cooling degree days, base 65°F
2,023
Growing degree days, base 40°F
7,949
Growing degree days, base 45°F
6,464
Growing degree days, base 50°F
5,134
Growing degree days, base 55°F
3,949
Growing degree days, base 60°F
2,914

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January820013
February638131
March4487136
April19837308
May43172594
June1403852
July05461,011
August0515979
September16279712
October16162380
November4763102
December777016

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 7.4 km from Greer 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 USC00345509 (Mangum). Public domain.