Gilmer County climate

Gilmer County Frost Dates and Growing Season

NOAA 1991-2020 normals for Glenville, 2.4 km from Gilmer County, elevation 738 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Glenville. 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 25 and the first fall freeze around October 24, a growing season of about 180 days.

Median at 36°F
last May 6, first October 15
Median at 32°F
last April 25, first October 24
Median at 28°F
last April 11, first November 2

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 22May 17May 13May 9May 6May 3Apr 30Apr 26Apr 21
32°FMay 15May 8May 4Apr 30Apr 25Apr 22Apr 19Apr 16Apr 11
28°FMay 3Apr 23Apr 18Apr 14Apr 11Apr 8Apr 5Apr 1Mar 27
24°FApr 13Apr 7Apr 4Apr 1Mar 29Mar 26Mar 22Mar 18Mar 13
20°FApr 1Mar 28Mar 24Mar 20Mar 17Mar 14Mar 10Mar 4Feb 28
16°FMar 21Mar 16Mar 12Mar 8Mar 5Mar 2Feb 27Feb 21Feb 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 1Oct 6Oct 10Oct 13Oct 15Oct 18Oct 21Oct 24Oct 27
32°FOct 9Oct 14Oct 19Oct 22Oct 24Oct 27Oct 30Nov 1Nov 5
28°FOct 20Oct 25Oct 29Nov 1Nov 2Nov 4Nov 7Nov 10Nov 15
24°FOct 31Nov 2Nov 5Nov 9Nov 11Nov 14Nov 17Nov 22Nov 28
20°FNov 6Nov 11Nov 16Nov 19Nov 23Nov 28Dec 1Dec 5Dec 14
16°FNov 16Nov 24Nov 29Dec 2Dec 6Dec 11Dec 17Dec 23Dec 30

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°F180174169165161156152148141
32°F199193188184180176171165157
28°F222215210207202198193187178
24°F249241235231227222217212204
20°F281271265259253248243237229
16°F307298291285279274268261251

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
4,959
Cooling degree days, base 65°F
943
Growing degree days, base 40°F
5,939
Growing degree days, base 45°F
4,636
Growing degree days, base 50°F
3,492
Growing degree days, base 55°F
2,497
Growing degree days, base 60°F
1,647

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,01707
February84008
March695146
April35910170
May14563390
June20185615
July1289753
August3263725
September57116509
October31017212
November624044
December888012

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 2.4 km from Gilmer County. 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 USC00463544 (Glenville). Public domain.