Greeneville climate

Greeneville Frost Dates and Growing Season

NOAA 1991-2020 normals for Greeneville Exp Stn, 6.5 km from Greeneville, elevation 1320 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Greeneville Exp Stn. 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 20 and the first fall freeze around October 22, a growing season of about 185 days.

Median at 36°F
last May 2, first October 13
Median at 32°F
last April 20, first October 22
Median at 28°F
last April 6, 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 16May 11May 8May 4May 2Apr 29Apr 26Apr 22Apr 18
32°FMay 8May 3Apr 28Apr 24Apr 20Apr 16Apr 13Apr 9Apr 4
28°FApr 24Apr 17Apr 13Apr 9Apr 6Apr 2Mar 31Mar 27Mar 22
24°FApr 10Apr 5Apr 1Mar 30Mar 26Mar 23Mar 19Mar 14Mar 6
20°FApr 1Mar 27Mar 23Mar 19Mar 14Mar 9Mar 4Feb 27Feb 19
16°FMar 23Mar 16Mar 8Mar 3Feb 27Feb 21Feb 14Feb 6Jan 29

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

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°F184178172168165161156151145
32°F206199194189185180175169162
28°F229222216211207203199192184
24°F253245238234229225220213206
20°F287275268261255249244238230
16°F320308300291285279272264255

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
4,165
Cooling degree days, base 65°F
1,182
Growing degree days, base 40°F
6,664
Growing degree days, base 45°F
5,248
Growing degree days, base 50°F
3,996
Growing degree days, base 55°F
2,905
Growing degree days, base 60°F
1,970

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January882016
February700022
March558282
April29017223
May9790462
June9232673
July0344809
August1308772
September35159575
October25427268
November555269
December785026

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 6.5 km from Greeneville. 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 USC00403679 (Greeneville Exp Stn). Public domain.