Jeff Davis County climate

Jeff Davis County Frost Dates and Growing Season

NOAA 1991-2020 normals for Mt Locke, 11.2 km from Jeff Davis County, elevation 6790 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mt Locke. 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 April 16 and the first fall freeze around October 29, a growing season of about 194 days.

Median at 36°F
last April 26, first October 19
Median at 32°F
last April 16, first October 29
Median at 28°F
last April 3, first November 6

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

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°FSep 30Oct 6Oct 12Oct 16Oct 19Oct 22Oct 25Oct 28Nov 1
32°FOct 12Oct 17Oct 21Oct 25Oct 29Nov 1Nov 4Nov 9Nov 14
28°FOct 19Oct 25Oct 31Nov 3Nov 6Nov 10Nov 14Nov 18Nov 25
24°FOct 29Nov 3Nov 8Nov 12Nov 16Nov 21Nov 25Nov 29Dec 6
20°FNov 6Nov 14Nov 20Nov 25Nov 29Dec 3Dec 8Dec 18Dec 29
16°FNov 19Nov 29Dec 3Dec 7Dec 13Dec 22Jan 1Jan 9Jan 25

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°F193187182177173168163158148
32°F219212205199194189184177168
28°F246235228223217212205198189
24°F277265256248240235229220210
20°F323309299288280272264254241
16°F362348338329319308301290273

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
99% of years
16°F or colder
91% 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
3,068
Cooling degree days, base 65°F
989
Growing degree days, base 40°F
7,245
Growing degree days, base 45°F
5,642
Growing degree days, base 50°F
4,189
Growing degree days, base 55°F
2,918
Growing degree days, base 60°F
1,848

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January660033
February504064
March3835160
April19725297
May64129533
June5247691
July5231691
August6210669
September44105513
October16036358
November4082134
December632043

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 11.2 km from Jeff Davis County. 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 USC00416104 (Mt Locke). Public domain.