Adair climate

Adair Frost Dates and Growing Season

NOAA 1991-2020 normals for Guthrie Ctr, 22.3 km from Adair, elevation 1065 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Guthrie Ctr. 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 2 and the first fall freeze around October 3, a growing season of about 153 days.

Median at 36°F
last May 12, first September 25
Median at 32°F
last May 2, first October 3
Median at 28°F
last April 23, first October 15

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 26May 22May 18May 15May 12May 9May 7May 4Apr 30
32°FMay 17May 11May 8May 5May 2Apr 30Apr 26Apr 22Apr 18
28°FMay 8May 3Apr 29Apr 26Apr 23Apr 19Apr 16Apr 13Apr 8
24°FApr 27Apr 22Apr 18Apr 14Apr 11Apr 8Apr 5Apr 2Mar 28
20°FApr 18Apr 10Apr 6Apr 4Apr 1Mar 30Mar 26Mar 22Mar 15
16°FApr 6Apr 2Mar 30Mar 27Mar 23Mar 19Mar 16Mar 12Mar 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 12Sep 16Sep 19Sep 22Sep 25Sep 28Oct 1Oct 3Oct 7
32°FSep 20Sep 25Sep 28Oct 1Oct 3Oct 5Oct 10Oct 13Oct 18
28°FSep 30Oct 4Oct 8Oct 12Oct 15Oct 17Oct 20Oct 23Oct 28
24°FOct 11Oct 16Oct 20Oct 22Oct 25Oct 27Oct 30Nov 1Nov 6
20°FOct 21Oct 25Oct 29Nov 1Nov 2Nov 4Nov 7Nov 11Nov 16
16°FOct 29Nov 2Nov 5Nov 8Nov 11Nov 14Nov 17Nov 22Nov 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°F152146143138134131127123118
32°F172166161158153149145139133
28°F194187182177173169164158152
24°F215209203199195191187182175
20°F237228223218214210206200192
16°F255248242238233228223217211

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
6,849
Cooling degree days, base 65°F
843
Growing degree days, base 40°F
5,121
Growing degree days, base 45°F
4,024
Growing degree days, base 50°F
3,044
Growing degree days, base 55°F
2,184
Growing degree days, base 60°F
1,449

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,40600
February1,14201
March885123
April4977106
May20654331
June28189611
July6286745
August16210659
September13186412
October45611137
November845019
December1,23200

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 22.3 km from Adair. 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 USC00133509 (Guthrie Ctr). Public domain.