Carter County climate

Carter County Frost Dates and Growing Season

NOAA 1991-2020 normals for Elizabethton, 12.8 km from Carter County, elevation 1487 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Elizabethton. 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 19 and the first fall freeze around October 24, a growing season of about 187 days.

Median at 36°F
last April 30, first October 16
Median at 32°F
last April 19, first October 24
Median at 28°F
last April 5, first November 1

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 17May 11May 7May 4Apr 30Apr 28Apr 24Apr 20Apr 15
32°FMay 7May 1Apr 27Apr 23Apr 19Apr 16Apr 12Apr 8Apr 2
28°FApr 23Apr 18Apr 13Apr 9Apr 5Apr 2Mar 31Mar 26Mar 20
24°FApr 9Apr 4Mar 31Mar 28Mar 25Mar 21Mar 16Mar 10Mar 2
20°FMar 30Mar 25Mar 19Mar 15Mar 10Mar 4Feb 28Feb 22Feb 13
16°FMar 19Mar 11Mar 5Feb 28Feb 23Feb 17Feb 11Feb 4Jan 26

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 4Oct 8Oct 11Oct 13Oct 16Oct 18Oct 21Oct 24Oct 29
32°FOct 10Oct 15Oct 18Oct 21Oct 24Oct 27Oct 30Nov 1Nov 5
28°FOct 19Oct 24Oct 27Oct 31Nov 1Nov 4Nov 7Nov 11Nov 15
24°FOct 30Nov 2Nov 5Nov 9Nov 12Nov 14Nov 18Nov 23Nov 29
20°FNov 7Nov 13Nov 16Nov 21Nov 24Nov 28Dec 1Dec 6Dec 16
16°FNov 16Nov 24Nov 30Dec 3Dec 7Dec 14Dec 21Dec 27Jan 3

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°F187181176170166163159154146
32°F208201195191187183178173164
28°F230223219213209205201195189
24°F256248242237232227223218211
20°F289277271265260254248241232
16°F322309301295288281275267255

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
4,303
Cooling degree days, base 65°F
1,008
Growing degree days, base 40°F
6,404
Growing degree days, base 45°F
5,009
Growing degree days, base 50°F
3,772
Growing degree days, base 55°F
2,695
Growing degree days, base 60°F
1,773

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January904013
February721018
March573177
April29913214
May10580445
June12199637
July1295759
August1270733
September42128536
October26921253
November574266
December801021

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 12.8 km from Carter 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 USC00402806 (Elizabethton). Public domain.