Florence climate

Florence Frost Dates and Growing Season

NOAA 1991-2020 normals for Muscle Shoals 2 N, 4.5 km from Florence, elevation 530 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Muscle Shoals 2 N. 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 27 and the first fall freeze around November 3, a growing season of about 220 days.

Median at 36°F
last April 10, first October 25
Median at 32°F
last March 27, first November 3
Median at 28°F
last March 12, first November 14

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 25Apr 21Apr 17Apr 13Apr 10Apr 7Apr 3Mar 31Mar 24
32°FApr 13Apr 7Apr 3Mar 31Mar 27Mar 24Mar 19Mar 15Mar 7
28°FMar 31Mar 26Mar 21Mar 16Mar 12Mar 8Mar 4Feb 27Feb 20
24°FMar 19Mar 12Mar 6Mar 2Feb 27Feb 23Feb 18Feb 11Feb 1
20°FMar 7Mar 1Feb 24Feb 18Feb 11Feb 7Feb 1Jan 26Jan 15
16°FFeb 26Feb 15Feb 8Feb 2Jan 29Jan 24Jan 19Jan 12Jan 5

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 14Oct 18Oct 21Oct 23Oct 25Oct 27Oct 30Nov 2Nov 7
32°FOct 22Oct 27Oct 30Nov 1Nov 3Nov 6Nov 9Nov 12Nov 19
28°FNov 1Nov 4Nov 8Nov 10Nov 14Nov 18Nov 22Nov 27Dec 2
24°FNov 9Nov 15Nov 19Nov 24Nov 29Dec 2Dec 7Dec 15Dec 28
20°FNov 21Dec 1Dec 6Dec 12Dec 22Dec 27Jan 1Jan 7Jan 15
16°FDec 8Dec 21Dec 29Jan 2Jan 6Jan 10Jan 15Jan 22Feb 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°F219211206201197193189185179
32°F245235229224220215210205198
28°F274265258252247243237230222
24°F307298289282275269263256247
20°F340330321314307302294285274
16°F365362352343335330323314304

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
98% of years
16°F or colder
83% 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
3,190
Cooling degree days, base 65°F
1,651
Growing degree days, base 40°F
7,853
Growing degree days, base 45°F
6,301
Growing degree days, base 50°F
4,886
Growing degree days, base 55°F
3,638
Growing degree days, base 60°F
2,558

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January749038
February562159
March3937158
April17337322
May47147566
June1325774
July0431896
August0411876
September13235672
October16452361
November4364109
December652155

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 4.5 km from Florence. 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 USW00063894 (Muscle Shoals 2 N). Public domain.