Alamo climate

Alamo Frost Dates and Growing Season

NOAA 1991-2020 normals for Pahranagat Wr, 11.3 km from Alamo, elevation 3334 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Pahranagat Wr. 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 3 and the first fall freeze around October 31, a growing season of about 212 days.

Median at 36°F
last April 21, first October 21
Median at 32°F
last April 3, first October 31
Median at 28°F
last March 12, first November 12

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 4Apr 30Apr 25Apr 21Apr 17Apr 13Apr 9Apr 3
32°FApr 21Apr 14Apr 9Apr 6Apr 3Mar 30Mar 25Mar 20Mar 12
28°FApr 4Mar 29Mar 22Mar 16Mar 12Mar 7Mar 4Feb 28Feb 21
24°FMar 14Mar 7Mar 2Feb 26Feb 22Feb 15Feb 9Feb 3Jan 25
20°FMar 1Feb 16Feb 7Jan 31Jan 25Jan 18Jan 11Jan 4Dec 28
16°FFeb 6Jan 27Jan 15Jan 9Jan 5Jan 1Dec 28Dec 21Dec 11

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 8Oct 13Oct 16Oct 19Oct 21Oct 24Oct 28Oct 31Nov 5
32°FOct 16Oct 21Oct 24Oct 28Oct 31Nov 3Nov 7Nov 12Nov 18
28°FOct 24Oct 30Nov 4Nov 8Nov 12Nov 16Nov 20Nov 25Nov 30
24°FNov 6Nov 12Nov 17Nov 21Nov 25Nov 28Dec 2Dec 6Dec 11
20°FNov 17Nov 25Nov 30Dec 4Dec 7Dec 11Dec 15Dec 21Jan 1
16°FNov 28Dec 5Dec 10Dec 14Dec 20Dec 26Jan 1Jan 6Jan 24

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°F205198192187183178172166158
32°F238230223218212207203197188
28°F271262255249243237231225213
24°F309298290284277272264256245
20°F346337330323316309302291278
16°F365365364356350342336330317

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
71% 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
3,410
Cooling degree days, base 65°F
1,861
Growing degree days, base 40°F
7,727
Growing degree days, base 45°F
6,173
Growing degree days, base 50°F
4,832
Growing degree days, base 55°F
3,680
Growing degree days, base 60°F
2,690

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January72104
February547020
March4131111
April22414254
May74131524
June6360804
July05581,023
August0511976
September11252692
October16333344
November476178
December77502

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 11.3 km from Alamo. 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 USC00265880 (Pahranagat Wr). Public domain.