Annville climate

Annville Frost Dates and Growing Season

NOAA 1991-2020 normals for Booneville 12SW, 18.1 km from Annville, elevation 880 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Booneville 12SW. 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 24 and the first fall freeze around October 19, a growing season of about 178 days.

Median at 36°F
last May 5, first October 11
Median at 32°F
last April 24, first October 19
Median at 28°F
last April 11, first October 28

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 11May 8May 5May 1Apr 29Apr 24Apr 20
32°FMay 12May 6May 1Apr 28Apr 24Apr 21Apr 18Apr 14Apr 9
28°FApr 30Apr 21Apr 17Apr 14Apr 11Apr 7Apr 4Mar 31Mar 26
24°FApr 11Apr 6Apr 3Mar 31Mar 29Mar 26Mar 22Mar 18Mar 11
20°FApr 1Mar 28Mar 24Mar 20Mar 16Mar 12Mar 9Mar 3Feb 22
16°FMar 21Mar 16Mar 12Mar 7Mar 3Feb 27Feb 20Feb 13Feb 3

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 6Oct 9Oct 11Oct 13Oct 15Oct 18Oct 22
32°FOct 7Oct 11Oct 14Oct 16Oct 19Oct 21Oct 24Oct 27Oct 31
28°FOct 15Oct 19Oct 22Oct 26Oct 28Oct 31Nov 2Nov 6Nov 11
24°FOct 27Nov 1Nov 2Nov 5Nov 8Nov 11Nov 14Nov 18Nov 26
20°FNov 5Nov 10Nov 13Nov 16Nov 20Nov 25Nov 29Dec 2Dec 8
16°FNov 14Nov 20Nov 27Dec 1Dec 4Dec 8Dec 14Dec 22Dec 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°F175170166162159155151146139
32°F196190185181178173169165157
28°F220214208203200196192186178
24°F248241235229224220215211204
20°F278269261256250245240234226
16°F307298291284279272266257248

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
4,654
Cooling degree days, base 65°F
993
Growing degree days, base 40°F
6,188
Growing degree days, base 45°F
4,838
Growing degree days, base 50°F
3,649
Growing degree days, base 55°F
2,620
Growing degree days, base 60°F
1,731

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January97309
February777016
March635161
April32713199
May12173423
June12192630
July2299763
August3269732
September54126523
October29418227
November606050
December849017

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 18.1 km from Annville. 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 USC00150860 (Booneville 12SW). Public domain.