Sylacauga climate

Sylacauga Frost Dates and Growing Season

NOAA 1991-2020 normals for Sylacauga 4 Ne, 5.2 km from Sylacauga, elevation 490 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sylacauga 4 Ne. 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 2 and the first fall freeze around October 31, a growing season of about 211 days.

Median at 36°F
last April 14, first October 23
Median at 32°F
last April 2, first October 31
Median at 28°F
last March 19, first November 8

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

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 10Oct 14Oct 17Oct 20Oct 23Oct 25Oct 28Nov 1Nov 4
32°FOct 16Oct 20Oct 24Oct 28Oct 31Nov 2Nov 5Nov 9Nov 15
28°FOct 24Oct 31Nov 2Nov 5Nov 8Nov 13Nov 17Nov 21Nov 30
24°FNov 2Nov 8Nov 13Nov 17Nov 22Nov 27Dec 1Dec 6Dec 17
20°FNov 12Nov 22Nov 30Dec 4Dec 9Dec 17Dec 27Jan 3Jan 13
16°FDec 1Dec 7Dec 17Dec 27Jan 1Jan 6Jan 12Jan 20Feb 1

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°F213206200196192188183177171
32°F238230222216211207202197189
28°F265255247242236230224219210
24°F299287277271265258252245236
20°F334323312305298290284274262
16°F365357345336330323315306293

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
99% of years
16°F or colder
85% 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
2,937
Cooling degree days, base 65°F
1,754
Growing degree days, base 40°F
8,140
Growing degree days, base 45°F
6,551
Growing degree days, base 50°F
5,108
Growing degree days, base 55°F
3,821
Growing degree days, base 60°F
2,702

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January684151
February518266
March35211189
April16244343
May38165592
June1337786
July0446911
August0415880
September12258696
October15265388
November4068140
December613265

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 5.2 km from Sylacauga. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00017999 (Sylacauga 4 Ne). Public domain.