Jacksons Gap climate

Jacksons Gap Frost Dates and Growing Season

NOAA 1991-2020 normals for Alexander City, 14.3 km from Jacksons Gap, elevation 640 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Alexander City. 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 March 26 and the first fall freeze around November 8, a growing season of about 227 days.

Median at 36°F
last April 8, first October 30
Median at 32°F
last March 26, first November 8
Median at 28°F
last March 12, first November 20

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°FApr 24Apr 18Apr 14Apr 11Apr 8Apr 5Apr 1Mar 29Mar 23
32°FApr 12Apr 6Apr 1Mar 30Mar 26Mar 23Mar 18Mar 13Mar 5
28°FMar 31Mar 26Mar 21Mar 16Mar 12Mar 7Mar 2Feb 26Feb 19
24°FMar 20Mar 13Mar 7Mar 2Feb 26Feb 20Feb 13Feb 5Jan 27
20°FMar 7Feb 28Feb 18Feb 12Feb 5Jan 31Jan 26Jan 19Jan 8
16°FFeb 22Feb 10Feb 4Jan 31Jan 26Jan 20Jan 16Jan 8Dec 31

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 18Oct 22Oct 25Oct 27Oct 30Nov 1Nov 3Nov 6Nov 11
32°FOct 27Nov 1Nov 2Nov 5Nov 8Nov 11Nov 14Nov 18Nov 26
28°FNov 4Nov 9Nov 13Nov 17Nov 20Nov 24Nov 29Dec 2Dec 11
24°FNov 15Nov 23Nov 28Dec 1Dec 5Dec 11Dec 21Dec 28Jan 5
20°FNov 28Dec 5Dec 11Dec 21Dec 28Jan 1Jan 7Jan 15Jan 28
16°FDec 11Dec 24Jan 1Jan 3Jan 8Jan 14Jan 19Jan 26Feb 6

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°F228219214210205201196191183
32°F255245238232227222218212206
28°F283274266259254249243237228
24°F325311302294287280271261252
20°F354342334327319311304297285
16°F365365365357347340333323308

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
94% of years
16°F or colder
68% 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
2,683
Cooling degree days, base 65°F
1,903
Growing degree days, base 40°F
8,481
Growing degree days, base 45°F
6,850
Growing degree days, base 50°F
5,363
Growing degree days, base 55°F
4,037
Growing degree days, base 60°F
2,882

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January650050
February487172
March32811202
April14146362
May28184622
June0365814
July0479944
August0446911
September6282726
October11576431
November3599159
December570270

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 14.3 km from Jacksons Gap. 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 USC00010160 (Alexander City). Public domain.