Walton climate

Walton Frost Dates and Growing Season

NOAA 1991-2020 normals for Walton 2, 2.1 km from Walton, elevation 1480 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Walton 2. 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 21 and the first fall freeze around October 1, a growing season of about 132 days.

Median at 36°F
last May 31, first September 22
Median at 32°F
last May 21, first October 1
Median at 28°F
last May 8, first October 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°FJun 18Jun 10Jun 6Jun 2May 31May 29May 26May 22May 17
32°FJun 5May 31May 27May 24May 21May 18May 14May 10May 2
28°FMay 24May 18May 14May 11May 8May 4Apr 30Apr 27Apr 23
24°FMay 12May 6May 1Apr 27Apr 23Apr 21Apr 18Apr 14Apr 8
20°FApr 26Apr 21Apr 17Apr 13Apr 9Apr 6Apr 4Apr 1Mar 29
16°FApr 13Apr 7Apr 5Apr 3Apr 1Mar 30Mar 27Mar 23Mar 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°FSep 10Sep 14Sep 17Sep 20Sep 22Sep 25Sep 27Sep 30Oct 3
32°FSep 20Sep 24Sep 27Sep 29Oct 1Oct 3Oct 6Oct 10Oct 14
28°FSep 30Oct 3Oct 5Oct 9Oct 12Oct 15Oct 19Oct 24Oct 31
24°FOct 6Oct 13Oct 17Oct 21Oct 26Oct 31Nov 3Nov 5Nov 11
20°FOct 20Oct 27Nov 1Nov 4Nov 7Nov 10Nov 13Nov 17Nov 21
16°FNov 3Nov 9Nov 12Nov 15Nov 18Nov 21Nov 25Nov 28Dec 2

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°F1301241191151111071049992
32°F154147141137132128124119111
28°F181172167162158153148143135
24°F206198192188183178173167159
20°F230223218214210205199194185
16°F250244238234231227223218213

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
7,565
Cooling degree days, base 65°F
246
Growing degree days, base 40°F
3,842
Growing degree days, base 45°F
2,827
Growing degree days, base 50°F
1,950
Growing degree days, base 55°F
1,216
Growing degree days, base 60°F
639

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,35001
February1,18000
March1,06005
April655138
May3609165
June12243373
July4091516
August5376488
September20525280
October536274
November84008
December1,16301

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 2.1 km from Walton. 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 USC00308932 (Walton 2). Public domain.