Christoval climate

Christoval Frost Dates and Growing Season

NOAA 1991-2020 normals for San Angelo WFO, 19.7 km from Christoval, elevation 1890 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for San Angelo WFO. 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 22 and the first fall freeze around November 10, a growing season of about 233 days.

Median at 36°F
last April 5, first November 2
Median at 32°F
last March 22, first November 10
Median at 28°F
last March 8, first November 21

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

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 20Oct 25Oct 28Oct 31Nov 2Nov 4Nov 7Nov 10Nov 14
32°FOct 28Nov 1Nov 4Nov 7Nov 10Nov 13Nov 16Nov 21Nov 28
28°FNov 4Nov 9Nov 14Nov 17Nov 21Nov 25Nov 29Dec 3Dec 8
24°FNov 14Nov 19Nov 25Nov 29Dec 2Dec 6Dec 11Dec 18Dec 28
20°FNov 26Dec 2Dec 8Dec 13Dec 20Dec 28Jan 3Jan 11Jan 24
16°FDec 6Dec 13Dec 23Jan 1Jan 5Jan 10Jan 17Jan 24Feb 6

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°F233225218213208205199194186
32°F260250244239233228223216208
28°F283273267262258252247239231
24°F316305296290283277271264254
20°F359344337328319310303295279
16°F365365365365358348340333314

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
93% of years
16°F or colder
59% 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
2,356
Cooling degree days, base 65°F
2,527
Growing degree days, base 40°F
9,424
Growing degree days, base 45°F
7,765
Growing degree days, base 50°F
6,229
Growing degree days, base 55°F
4,833
Growing degree days, base 60°F
3,595

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January598160
February4206120
March26329272
April91114479
May18301749
June0478928
July05671,032
August05551,020
September6334779
October86124508
November32016205
December553279

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 19.7 km from Christoval. 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 USC00417944 (San Angelo WFO). Public domain.