Forest climate

Forest Frost Dates and Growing Season

NOAA 1991-2020 normals for Lynchburg #2, 5.4 km from Forest, elevation 736 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lynchburg #2. 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 17 and the first fall freeze around October 25, a growing season of about 190 days.

Median at 36°F
last April 30, first October 15
Median at 32°F
last April 17, first October 25
Median at 28°F
last April 2, first November 3

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

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°F188182177173169165161156148
32°F209202198194190186182176168
28°F234226221217213210206202194
24°F264255248243238234228223216
20°F294284278272266261255249241
16°F327318310304297290284277265

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
4,489
Cooling degree days, base 65°F
966
Growing degree days, base 40°F
6,141
Growing degree days, base 45°F
4,778
Growing degree days, base 50°F
3,589
Growing degree days, base 55°F
2,561
Growing degree days, base 60°F
1,681

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January91609
February75609
March613159
April32413184
May11961409
June14193628
July1308772
August3268730
September51110509
October28614222
November580146
December826013

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 5.4 km from Forest. 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 USC00445117 (Lynchburg #2). Public domain.