Douglas climate

Douglas Frost Dates and Growing Season

NOAA 1991-2020 normals for Guntersville, 17.8 km from Douglas, elevation 578 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Guntersville. 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 19 and the first fall freeze around November 18, a growing season of about 244 days.

Median at 36°F
last April 1, first November 7
Median at 32°F
last March 19, first November 18
Median at 28°F
last March 6, first December 1

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 17Apr 11Apr 7Apr 4Apr 1Mar 30Mar 26Mar 22Mar 15
32°FApr 5Mar 31Mar 27Mar 23Mar 19Mar 15Mar 10Mar 4Feb 28
28°FMar 25Mar 19Mar 15Mar 10Mar 6Mar 2Feb 27Feb 21Feb 13
24°FMar 15Mar 8Mar 1Feb 26Feb 21Feb 14Feb 8Feb 1Jan 23
20°FMar 2Feb 24Feb 14Feb 7Feb 2Jan 30Jan 23Jan 15Jan 5
16°FFeb 21Feb 7Feb 1Jan 29Jan 24Jan 18Jan 13Jan 7Dec 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 27Oct 31Nov 1Nov 4Nov 7Nov 10Nov 13Nov 18Nov 25
32°FNov 2Nov 7Nov 11Nov 14Nov 18Nov 21Nov 26Dec 1Dec 6
28°FNov 11Nov 17Nov 23Nov 27Dec 1Dec 4Dec 10Dec 18Dec 30
24°FNov 24Dec 1Dec 6Dec 12Dec 20Dec 25Jan 1Jan 6Jan 14
20°FDec 9Dec 20Dec 27Jan 1Jan 4Jan 9Jan 13Jan 19Feb 1
16°FDec 23Dec 30Jan 2Jan 6Jan 10Jan 14Jan 19Jan 27Feb 4

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°F246236229224219214211205199
32°F271261254249244239233228219
28°F303290281274268263257250241
24°F334325316306300294287280270
20°F365354345336331324315306295
16°F365365365365355346339333321

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
99% of years
20°F or colder
88% of years
16°F or colder
60% 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
2,995
Cooling degree days, base 65°F
1,910
Growing degree days, base 40°F
8,254
Growing degree days, base 45°F
6,674
Growing degree days, base 50°F
5,242
Growing degree days, base 55°F
3,968
Growing degree days, base 60°F
2,859

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January721034
February552150
March3799168
April16044346
May33176608
June1364813
July0473938
August0462927
September6296739
October12277427
November3938139
December628154

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 17.8 km from Douglas. 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 USC00013573 (Guntersville). Public domain.