Allison climate

Allison Frost Dates and Growing Season

NOAA 1991-2020 normals for Allison, 0.6 km from Allison, elevation 1038 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Allison. 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 27 and the first fall freeze around October 8, a growing season of about 165 days.

Median at 36°F
last May 5, first September 30
Median at 32°F
last April 27, first October 8
Median at 28°F
last April 16, first October 20

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 16May 12May 9May 7May 5May 3May 1Apr 28Apr 23
32°FMay 8May 5May 2Apr 30Apr 27Apr 24Apr 21Apr 17Apr 12
28°FApr 30Apr 26Apr 22Apr 19Apr 16Apr 13Apr 10Apr 7Apr 2
24°FApr 22Apr 16Apr 12Apr 9Apr 6Apr 4Apr 1Mar 28Mar 22
20°FApr 14Apr 8Apr 4Apr 1Mar 30Mar 26Mar 23Mar 19Mar 13
16°FApr 6Mar 31Mar 28Mar 24Mar 21Mar 17Mar 14Mar 10Mar 6

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 17Sep 21Sep 24Sep 27Sep 30Oct 2Oct 5Oct 8Oct 12
32°FSep 24Sep 29Oct 2Oct 5Oct 8Oct 11Oct 14Oct 18Oct 22
28°FOct 4Oct 9Oct 13Oct 17Oct 20Oct 21Oct 24Oct 28Nov 1
24°FOct 15Oct 20Oct 22Oct 26Oct 29Oct 31Nov 3Nov 6Nov 10
20°FOct 25Oct 29Nov 1Nov 3Nov 6Nov 9Nov 12Nov 16Nov 21
16°FNov 2Nov 5Nov 8Nov 11Nov 14Nov 17Nov 21Nov 24Nov 29

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°F165159154151147144141136129
32°F186179173169165161157153146
28°F203197192189185182177172166
24°F224217212208204200195191185
20°F241235230226221217212207201
16°F260252247243238234230225217

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
7,358
Cooling degree days, base 65°F
711
Growing degree days, base 40°F
4,864
Growing degree days, base 45°F
3,806
Growing degree days, base 50°F
2,854
Growing degree days, base 55°F
2,016
Growing degree days, base 60°F
1,298

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,51100
February1,24700
March969015
April537381
May21743310
June28164586
July5246705
August16181629
September13567389
October4738124
November905013
December1,31600

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 0.6 km from Allison. 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 USC00130157 (Allison). Public domain.