Capitan climate

Capitan Frost Dates and Growing Season

NOAA 1991-2020 normals for Capitan, 2.6 km from Capitan, elevation 6480 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Capitan. 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 May 3 and the first fall freeze around October 12, a growing season of about 161 days.

Median at 36°F
last May 13, first October 3
Median at 32°F
last May 3, first October 12
Median at 28°F
last April 24, first October 24

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 25May 20May 17May 15May 13May 10May 7May 4Apr 30
32°FMay 17May 12May 8May 5May 3May 1Apr 29Apr 25Apr 20
28°FMay 8May 3Apr 30Apr 27Apr 24Apr 21Apr 18Apr 14Apr 7
24°FApr 30Apr 23Apr 19Apr 14Apr 9Apr 5Apr 2Mar 28Mar 19
20°FApr 18Apr 9Apr 4Mar 30Mar 26Mar 20Mar 15Mar 8Mar 1
16°FMar 30Mar 22Mar 14Mar 9Mar 4Feb 27Feb 21Feb 12Feb 2

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 22Sep 27Sep 29Oct 1Oct 3Oct 5Oct 8Oct 11Oct 15
32°FOct 1Oct 4Oct 6Oct 10Oct 12Oct 15Oct 17Oct 20Oct 23
28°FOct 10Oct 15Oct 18Oct 21Oct 24Oct 26Oct 30Nov 1Nov 5
24°FOct 20Oct 25Oct 28Oct 31Nov 3Nov 5Nov 8Nov 13Nov 17
20°FOct 28Nov 2Nov 5Nov 8Nov 12Nov 16Nov 20Nov 24Nov 30
16°FNov 4Nov 10Nov 16Nov 22Nov 26Nov 30Dec 3Dec 7Dec 14

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°F158153149146143140135131125
32°F178172168164161157153149144
28°F204196190186182178174169162
24°F230221215210206201195190182
20°F264253243237231225219213204
16°F301290280273266258251243233

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
100% of years
16°F or colder
100% 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
4,600
Cooling degree days, base 65°F
444
Growing degree days, base 40°F
5,384
Growing degree days, base 45°F
4,000
Growing degree days, base 50°F
2,819
Growing degree days, base 55°F
1,838
Growing degree days, base 60°F
1,048

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January85601
February68206
March595033
April3761125
May16423328
June14130565
July4156617
August7108566
September8927390
October3351161
November611025
December86803

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 2.6 km from Capitan. 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 USC00291440 (Capitan). Public domain.