Central High climate

Central High Frost Dates and Growing Season

NOAA 1991-2020 normals for Duncan, 18.1 km from Central High, elevation 1125 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Duncan. 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 March 25 and the first fall freeze around November 7, a growing season of about 225 days.

Median at 36°F
last April 7, first October 30
Median at 32°F
last March 25, first November 7
Median at 28°F
last March 11, first November 16

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

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°F227219213209205200195190183
32°F251243236231225222216209200
28°F272265258253249243238232223
24°F299288281275270264259253245
20°F327315308302296289282274264
16°F361349337329322313306300288

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
93% 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
3,203
Cooling degree days, base 65°F
2,091
Growing degree days, base 40°F
8,312
Growing degree days, base 45°F
6,769
Growing degree days, base 50°F
5,375
Growing degree days, base 55°F
4,128
Growing degree days, base 60°F
3,032

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January770018
February583148
March38412179
April16248350
May33180612
June1398847
July05441,009
August0527992
September14300736
October13274416
November4156136
December708030

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 18.1 km from Central High. 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 USC00342660 (Duncan). Public domain.