Altavista climate

Altavista Frost Dates and Growing Season

NOAA 1991-2020 normals for Lynchburg Rgnl AP, 24.3 km from Altavista, elevation 940 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lynchburg Rgnl AP. 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 15 and the first fall freeze around October 24, a growing season of about 191 days.

Median at 36°F
last April 28, first October 15
Median at 32°F
last April 15, first October 24
Median at 28°F
last April 1, 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 1Apr 28Apr 25Apr 21Apr 17Apr 13
32°FMay 3Apr 27Apr 21Apr 18Apr 15Apr 12Apr 8Apr 4Mar 30
28°FApr 15Apr 10Apr 7Apr 4Apr 1Mar 29Mar 26Mar 21Mar 16
24°FApr 5Mar 31Mar 28Mar 24Mar 21Mar 18Mar 14Mar 9Mar 3
20°FMar 25Mar 19Mar 15Mar 11Mar 7Mar 4Feb 28Feb 23Feb 15
16°FMar 17Mar 10Mar 4Feb 28Feb 24Feb 17Feb 10Feb 4Jan 27

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 12Oct 15Oct 18Oct 21Oct 24Oct 28
32°FOct 12Oct 15Oct 19Oct 22Oct 24Oct 27Oct 30Nov 1Nov 5
28°FOct 20Oct 25Oct 29Nov 1Nov 3Nov 5Nov 8Nov 12Nov 18
24°FOct 31Nov 4Nov 8Nov 11Nov 14Nov 18Nov 22Nov 26Dec 2
20°FNov 9Nov 15Nov 21Nov 25Nov 29Dec 3Dec 7Dec 13Dec 22
16°FNov 25Dec 1Dec 6Dec 11Dec 17Dec 23Dec 28Jan 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°F189181177172168165161156150
32°F211204200195191186182176169
28°F238229224220215211207202195
24°F266257250245241235229224216
20°F298287280274269263257250242
16°F327316310304297291285277266

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
4,295
Cooling degree days, base 65°F
1,115
Growing degree days, base 40°F
6,461
Growing degree days, base 45°F
5,073
Growing degree days, base 50°F
3,846
Growing degree days, base 55°F
2,778
Growing degree days, base 60°F
1,870

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January902010
February734014
March578274
April28419221
May10681442
June12221659
July1340804
August2296759
September46136540
October26719243
November556165
December808017

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 24.3 km from Altavista. 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 USW00013733 (Lynchburg Rgnl AP). Public domain.