Andrews climate

Andrews Frost Dates and Growing Season

NOAA 1991-2020 normals for Andrews, 1.3 km from Andrews, elevation 1749 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Andrews. 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 17 and the first fall freeze around October 23, a growing season of about 189 days.

Median at 36°F
last April 30, first October 14
Median at 32°F
last April 17, first October 23
Median at 28°F
last April 1, first November 1

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 15May 9May 5May 2Apr 30Apr 26Apr 23Apr 19Apr 15
32°FMay 3Apr 27Apr 23Apr 20Apr 17Apr 14Apr 11Apr 7Apr 1
28°FApr 19Apr 13Apr 8Apr 4Apr 1Mar 30Mar 26Mar 21Mar 14
24°FApr 5Mar 31Mar 27Mar 24Mar 19Mar 15Mar 10Mar 3Feb 25
20°FMar 25Mar 17Mar 12Mar 7Mar 1Feb 26Feb 20Feb 13Feb 6
16°FMar 13Mar 4Feb 27Feb 20Feb 14Feb 8Feb 2Jan 29Jan 18

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 3Oct 7Oct 9Oct 12Oct 14Oct 17Oct 20Oct 23Oct 27
32°FOct 10Oct 14Oct 18Oct 20Oct 23Oct 25Oct 28Nov 1Nov 5
28°FOct 18Oct 23Oct 26Oct 29Nov 1Nov 4Nov 7Nov 10Nov 16
24°FOct 30Nov 3Nov 7Nov 10Nov 13Nov 16Nov 20Nov 26Dec 1
20°FNov 9Nov 15Nov 19Nov 25Nov 30Dec 2Dec 6Dec 13Dec 26
16°FNov 24Dec 2Dec 7Dec 13Dec 20Dec 26Jan 1Jan 6Jan 18

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°F186179175170167164160155148
32°F209202197193189185181175167
28°F235227221216212208203199192
24°F267258250245239234229222215
20°F307292283276271264259252242
16°F341328321314306298290282272

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
98% 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
3,933
Cooling degree days, base 65°F
975
Growing degree days, base 40°F
6,519
Growing degree days, base 45°F
5,058
Growing degree days, base 50°F
3,775
Growing degree days, base 55°F
2,669
Growing degree days, base 60°F
1,735

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January826012
February658017
March517177
April2899204
May9663436
June12195633
July1289753
August2262725
September28137559
October23818268
November531272
December736018

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 1.3 km from Andrews. 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 USC00310184 (Andrews). Public domain.