Carroll County climate

Carroll County Frost Dates and Growing Season

NOAA 1991-2020 normals for Galax Radio Wbrf, 17.8 km from Carroll County, elevation 2385 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Galax Radio Wbrf. 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 26 and the first fall freeze around October 14, a growing season of about 171 days.

Median at 36°F
last May 7, first October 6
Median at 32°F
last April 26, first October 14
Median at 28°F
last April 13, first October 25

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

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 24Sep 28Oct 1Oct 4Oct 6Oct 9Oct 11Oct 15Oct 20
32°FOct 1Oct 6Oct 8Oct 11Oct 14Oct 17Oct 20Oct 24Oct 29
28°FOct 10Oct 15Oct 18Oct 22Oct 25Oct 28Nov 1Nov 3Nov 7
24°FOct 18Oct 24Oct 29Nov 1Nov 4Nov 7Nov 10Nov 13Nov 21
20°FNov 1Nov 5Nov 9Nov 13Nov 17Nov 21Nov 26Dec 1Dec 6
16°FNov 11Nov 18Nov 24Nov 29Dec 2Dec 6Dec 12Dec 20Dec 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°F171165160155151147143138130
32°F192184180175171167162156149
28°F215208203198194190184177170
24°F241234227222219214210204197
20°F274264256250244240235229219
16°F309297288282275269262255246

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
5,111
Cooling degree days, base 65°F
582
Growing degree days, base 40°F
5,368
Growing degree days, base 45°F
4,077
Growing degree days, base 50°F
2,956
Growing degree days, base 55°F
2,003
Growing degree days, base 60°F
1,207

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January99703
February81205
March693033
April3924136
May16731337
June31118537
July4204665
August8166623
September8956419
October3664156
November657032
December896010

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 17.8 km from Carroll County. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00443267 (Galax Radio Wbrf). Public domain.