Lee County climate

Lee County Frost Dates and Growing Season

NOAA 1991-2020 normals for Pennington Gap, 12 km from Lee County, elevation 1360 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Pennington Gap. 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 22 and the first fall freeze around October 20, a growing season of about 179 days.

Median at 36°F
last May 3, first October 11
Median at 32°F
last April 22, first October 20
Median at 28°F
last April 10, first October 29

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 20May 15May 10May 7May 3Apr 30Apr 28Apr 24Apr 20
32°FMay 10May 4Apr 30Apr 26Apr 22Apr 20Apr 17Apr 14Apr 9
28°FApr 26Apr 20Apr 17Apr 13Apr 10Apr 7Apr 4Mar 31Mar 25
24°FApr 12Apr 6Apr 3Mar 31Mar 28Mar 24Mar 20Mar 16Mar 10
20°FMar 31Mar 25Mar 20Mar 17Mar 14Mar 9Mar 5Feb 28Feb 22
16°FMar 20Mar 13Mar 8Mar 3Feb 28Feb 24Feb 19Feb 12Feb 4

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 4Oct 7Oct 9Oct 11Oct 13Oct 16Oct 19Oct 23
32°FOct 8Oct 12Oct 15Oct 17Oct 20Oct 22Oct 25Oct 28Nov 1
28°FOct 15Oct 20Oct 24Oct 26Oct 29Nov 1Nov 3Nov 6Nov 11
24°FOct 25Oct 31Nov 2Nov 5Nov 8Nov 11Nov 15Nov 20Nov 25
20°FNov 5Nov 10Nov 13Nov 16Nov 21Nov 25Nov 29Dec 3Dec 10
16°FNov 16Nov 23Nov 28Dec 1Dec 4Dec 9Dec 13Dec 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°F177171166163159155152147140
32°F197190186182179175170165158
28°F223215209205201197193187180
24°F251241235231226222218212205
20°F283273265260254248243237229
16°F313302294288282276269262253

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
4,620
Cooling degree days, base 65°F
938
Growing degree days, base 40°F
6,092
Growing degree days, base 45°F
4,748
Growing degree days, base 50°F
3,566
Growing degree days, base 55°F
2,541
Growing degree days, base 60°F
1,663

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January96105
February770010
March614056
April3338181
May12563409
June15187622
July1282745
August2258721
September45125530
October29317230
November605047
December857010

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 km from Lee 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 USC00446626 (Pennington Gap). Public domain.