Leighton climate

Leighton Frost Dates and Growing Season

NOAA 1991-2020 normals for Muscle Shoals Rgnl AP, 8.1 km from Leighton, elevation 540 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Muscle Shoals Rgnl AP. 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 20 and the first fall freeze around November 8, a growing season of about 233 days.

Median at 36°F
last April 2, first October 29
Median at 32°F
last March 20, first November 8
Median at 28°F
last March 6, 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 16Apr 10Apr 7Apr 4Apr 2Mar 30Mar 27Mar 23Mar 17
32°FApr 6Apr 1Mar 28Mar 24Mar 20Mar 16Mar 13Mar 8Feb 28
28°FMar 25Mar 18Mar 14Mar 11Mar 6Mar 2Feb 26Feb 21Feb 14
24°FMar 13Mar 6Mar 1Feb 25Feb 20Feb 16Feb 10Feb 4Jan 28
20°FMar 1Feb 22Feb 15Feb 10Feb 4Jan 31Jan 25Jan 18Jan 7
16°FFeb 22Feb 10Feb 3Jan 30Jan 25Jan 20Jan 15Jan 8Jan 1

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 16Oct 20Oct 23Oct 26Oct 29Oct 31Nov 3Nov 6Nov 11
32°FOct 25Oct 31Nov 2Nov 5Nov 8Nov 11Nov 15Nov 19Nov 26
28°FNov 4Nov 9Nov 12Nov 16Nov 20Nov 24Nov 29Dec 3Dec 9
24°FNov 15Nov 22Nov 29Dec 3Dec 6Dec 12Dec 19Dec 28Jan 4
20°FDec 2Dec 9Dec 16Dec 24Dec 30Jan 2Jan 7Jan 14Jan 24
16°FDec 15Dec 28Jan 1Jan 5Jan 9Jan 14Jan 18Jan 25Feb 3

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°F231224219214211206201197190
32°F257249243238233229224218211
28°F290278271265260254249243235
24°F326313305296289283276269258
20°F359346337329323318310304290
16°F365365365359351344335329319

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
2,822
Cooling degree days, base 65°F
2,096
Growing degree days, base 40°F
8,584
Growing degree days, base 45°F
6,986
Growing degree days, base 50°F
5,528
Growing degree days, base 55°F
4,225
Growing degree days, base 60°F
3,081

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January684147
February514268
March34716196
April13068395
May22219662
June0402852
July0512976
August0482947
September8298741
October12784428
November3849150
December605365

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 8.1 km from Leighton. 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 USW00013896 (Muscle Shoals Rgnl AP). Public domain.