Fulton County climate

Fulton County Frost Dates and Growing Season

NOAA 1991-2020 normals for Havana, 22.4 km from Fulton County, elevation 463 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Havana. 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 17 and the first fall freeze around October 19, a growing season of about 185 days.

Median at 36°F
last April 26, first October 8
Median at 32°F
last April 17, first October 19
Median at 28°F
last April 5, first October 29

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°FMay 11May 6May 2Apr 30Apr 26Apr 23Apr 20Apr 17Apr 13
32°FMay 3Apr 26Apr 22Apr 19Apr 17Apr 14Apr 10Apr 7Apr 2
28°FApr 21Apr 15Apr 11Apr 8Apr 5Apr 3Apr 1Mar 28Mar 22
24°FApr 10Apr 4Apr 1Mar 31Mar 28Mar 24Mar 20Mar 16Mar 11
20°FApr 1Mar 27Mar 23Mar 20Mar 17Mar 14Mar 11Mar 7Mar 2
16°FMar 23Mar 18Mar 14Mar 11Mar 8Mar 5Mar 2Feb 26Feb 19

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°FSep 24Sep 29Oct 1Oct 5Oct 8Oct 11Oct 13Oct 17Oct 21
32°FOct 1Oct 9Oct 13Oct 16Oct 19Oct 21Oct 23Oct 27Oct 31
28°FOct 15Oct 20Oct 24Oct 26Oct 29Nov 1Nov 3Nov 6Nov 13
24°FOct 26Oct 31Nov 3Nov 5Nov 9Nov 13Nov 16Nov 19Nov 25
20°FNov 6Nov 10Nov 14Nov 17Nov 21Nov 24Nov 27Dec 1Dec 6
16°FNov 13Nov 18Nov 23Nov 26Nov 29Dec 2Dec 5Dec 10Dec 16

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°F182175171167163158155149142
32°F202197192188185181175170162
28°F226219213207204201197191185
24°F249240235231226223219213206
20°F269262256252248244240234226
16°F288280275269266262256251245

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
100% 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
5,686
Cooling degree days, base 65°F
1,161
Growing degree days, base 40°F
5,950
Growing degree days, base 45°F
4,746
Growing degree days, base 50°F
3,666
Growing degree days, base 55°F
2,698
Growing degree days, base 60°F
1,859

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,24100
February99103
March754136
April39212155
May12886427
June15258693
July0360824
August3296758
September71129511
October33319210
November688146
December1,07103

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 22.4 km from Fulton County. 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 USC00113940 (Havana). Public domain.