Pearsall climate

Pearsall Frost Dates and Growing Season

NOAA 1991-2020 normals for Dilley, 25 km from Pearsall, elevation 550 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Dilley. 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 16 and the first fall freeze around December 6, a growing season of about 296 days.

Median at 36°F
last March 2, first November 23
Median at 32°F
last February 16, first December 6
Median at 28°F
last January 26, first December 23

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 22Mar 16Mar 11Mar 6Mar 2Feb 27Feb 22Feb 16Feb 6
32°FMar 12Mar 4Feb 28Feb 21Feb 16Feb 8Feb 1Jan 26Jan 14
28°FMar 1Feb 19Feb 10Feb 2Jan 26Jan 16Jan 7Dec 30Dec 19
24°FFeb 16Feb 7Jan 25Jan 16Jan 6Jan 1Dec 28Dec 19Dec 12
20°F–––––––––
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 16Nov 20Nov 23Nov 28Dec 1Dec 5Dec 11
32°FNov 16Nov 23Nov 28Dec 3Dec 6Dec 11Dec 16Dec 24Jan 3
28°FDec 1Dec 6Dec 12Dec 17Dec 23Dec 29Jan 4Jan 17Feb 4
24°FDec 9Dec 14Dec 21Dec 27Jan 1Jan 3Jan 13Jan 24Feb 7
20°F–––––––––
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°F295285277272266261255248238
32°F336324312304296289280272261
28°F365361351343336328317309297
24°F365365365365365364355344329
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
83% of years
24°F or colder
38% of years
20°F or colder
9% 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
1,243
Cooling degree days, base 65°F
3,456
Growing degree days, base 40°F
11,354
Growing degree days, base 45°F
9,565
Growing degree days, base 50°F
7,844
Growing degree days, base 55°F
6,233
Growing degree days, base 60°F
4,763

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January36111174
February22429250
March109103467
April24227653
May1426890
June05641,014
July06321,097
August06481,113
September1469918
October27261700
November15873378
December33915192

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 25 km from Pearsall. 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 USC00412458 (Dilley). Public domain.