Brewster County climate

Brewster County Frost Dates and Growing Season

NOAA 1991-2020 normals for Persimmon Gap, 18.5 km from Brewster County, elevation 2865 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Persimmon Gap. 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 5 and the first fall freeze around November 20, a growing season of about 259 days.

Median at 36°F
last March 18, first November 10
Median at 32°F
last March 5, first November 20
Median at 28°F
last February 21, first December 2

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 6Apr 1Mar 28Mar 23Mar 18Mar 14Mar 10Mar 6Feb 28
32°FMar 26Mar 17Mar 12Mar 9Mar 5Mar 2Feb 27Feb 22Feb 17
28°FMar 10Mar 4Feb 28Feb 26Feb 21Feb 15Feb 10Feb 2Jan 22
24°FFeb 28Feb 21Feb 13Feb 5Jan 31Jan 22Jan 14Jan 6Dec 30
20°FFeb 16Feb 1Jan 19Jan 12Jan 7Jan 2Dec 30Dec 23Dec 12
16°FJan 25Jan 13Jan 8Jan 5Jan 1Dec 28Dec 20Dec 13Dec 8

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 28Nov 1Nov 5Nov 7Nov 10Nov 12Nov 15Nov 18Nov 24
32°FNov 5Nov 10Nov 13Nov 16Nov 20Nov 23Nov 27Dec 1Dec 5
28°FNov 14Nov 20Nov 25Nov 29Dec 2Dec 5Dec 10Dec 15Dec 21
24°FNov 26Dec 1Dec 6Dec 12Dec 17Dec 22Dec 27Jan 1Jan 13
20°FDec 6Dec 13Dec 21Dec 26Dec 30Jan 2Jan 7Jan 15Feb 1
16°FDec 7Dec 11Dec 16Dec 27Dec 31Jan 3Jan 8Jan 12Jan 22

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°F257250244240235229224218210
32°F283275269264259254248243232
28°F318306298291286280274267260
24°F355344336331323316308299287
20°F365365365365359353344336325
16°F365365365365365365365365356

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
95% of years
20°F or colder
57% of years
16°F or colder
14% 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
1,789
Cooling degree days, base 65°F
3,037
Growing degree days, base 40°F
10,419
Growing degree days, base 45°F
8,677
Growing degree days, base 50°F
7,036
Growing degree days, base 55°F
5,537
Growing degree days, base 60°F
4,204

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January498079
February3216156
March16150369
April36176591
May5414874
June05821,032
July06191,084
August06011,066
September3395842
October49176595
November24319258
December475190

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 18.5 km from Brewster 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 USC00416959 (Persimmon Gap). Public domain.