Section climate

Section Frost Dates and Growing Season

NOAA 1991-2020 normals for Scottsboro, 12.2 km from Section, elevation 615 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Scottsboro. 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 4 and the first fall freeze around October 30, a growing season of about 209 days.

Median at 36°F
last April 17, first October 21
Median at 32°F
last April 4, first October 30
Median at 28°F
last March 22, 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 26Apr 23Apr 20Apr 17Apr 14Apr 10Apr 7Apr 2
32°FApr 20Apr 15Apr 11Apr 7Apr 4Apr 1Mar 29Mar 25Mar 18
28°FApr 7Apr 2Mar 30Mar 26Mar 22Mar 18Mar 14Mar 8Mar 1
24°FMar 28Mar 22Mar 18Mar 13Mar 9Mar 4Feb 28Feb 23Feb 14
20°FMar 18Mar 10Mar 4Feb 28Feb 23Feb 15Feb 8Feb 1Jan 24
16°FMar 6Feb 26Feb 15Feb 7Feb 1Jan 29Jan 23Jan 14Jan 4

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 9Oct 13Oct 16Oct 19Oct 21Oct 24Oct 26Oct 30Nov 3
32°FOct 17Oct 21Oct 24Oct 27Oct 30Nov 1Nov 4Nov 7Nov 12
28°FOct 26Oct 31Nov 2Nov 5Nov 8Nov 11Nov 15Nov 21Nov 29
24°FNov 4Nov 9Nov 13Nov 18Nov 22Nov 26Dec 1Dec 5Dec 15
20°FNov 13Nov 21Nov 27Dec 2Dec 6Dec 12Dec 20Dec 29Jan 5
16°FNov 27Dec 5Dec 13Dec 22Dec 28Jan 1Jan 6Jan 12Jan 27

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°F208201196191188184180175168
32°F231223217213209205200195188
28°F257247241237232228223218211
24°F289277271263258252247240229
20°F327314305296289283276268260
16°F362348339332324316306298288

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
92% 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
3,433
Cooling degree days, base 65°F
1,565
Growing degree days, base 40°F
7,557
Growing degree days, base 45°F
6,042
Growing degree days, base 50°F
4,680
Growing degree days, base 55°F
3,480
Growing degree days, base 60°F
2,443

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January781026
February607136
March4404130
April20627291
May55131541
June3308756
July0415880
August0397862
September15228663
October17548351
November4615106
December691140

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 12.2 km from Section. 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 USC00017304 (Scottsboro). Public domain.