Cotulla climate

Cotulla Frost Dates and Growing Season

NOAA 1991-2020 normals for Cotulla La Salle CO AP, 2.7 km from Cotulla, elevation 476 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Cotulla La Salle CO AP. 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 February 11 and the first fall freeze around December 3, a growing season of about 300 days.

Median at 36°F
last March 1, first November 23
Median at 32°F
last February 11, first December 3
Median at 28°F
last January 20, first December 19

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°FMar 23Mar 13Mar 9Mar 5Mar 1Feb 25Feb 19Feb 13Feb 1
32°FMar 9Mar 2Feb 24Feb 17Feb 11Feb 3Jan 28Jan 19Jan 5
28°FFeb 28Feb 13Feb 5Jan 28Jan 20Jan 12Jan 5Dec 28Dec 15
24°FFeb 14Feb 1Jan 20Jan 13Jan 7Jan 3Dec 28Dec 21Dec 8
20°FFeb 1Jan 19Jan 15Jan 9Jan 5Jan 1Dec 29Dec 24Dec 12
16°F–––––––––

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°FNov 5Nov 11Nov 15Nov 19Nov 23Nov 27Dec 1Dec 5Dec 14
32°FNov 15Nov 22Nov 27Nov 30Dec 3Dec 8Dec 14Dec 25Jan 5
28°FNov 25Dec 1Dec 5Dec 11Dec 19Dec 26Jan 1Jan 9Jan 24
24°FDec 4Dec 11Dec 18Dec 27Jan 1Jan 4Jan 8Jan 16Feb 1
20°FDec 11Dec 20Dec 28Jan 1Jan 4Jan 7Jan 12Jan 17Jan 31
16°F–––––––––

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°F302289281274269264258250240
32°F339326317307300290282273262
28°F365363351343337329321310295
24°F365365365365365365357347333
20°F365365365365365365365365365
16°F365365365365365365365365365

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
99% of years
28°F or colder
82% of years
24°F or colder
41% of years
20°F or colder
11% of years
16°F or colder
1% 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
1,004
Cooling degree days, base 65°F
3,951
Growing degree days, base 40°F
12,079
Growing degree days, base 45°F
10,276
Growing degree days, base 50°F
8,524
Growing degree days, base 55°F
6,867
Growing degree days, base 60°F
5,337

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January31223217
February17461324
March77146538
April17267701
May1487952
June06221,072
July06811,146
August07021,167
September0521971
October16317766
November12597430
December28228241

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 2.7 km from Cotulla. 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 USW00012947 (Cotulla La Salle CO AP). Public domain.