Jackson County climate

Jackson County Frost Dates and Growing Season

NOAA 1991-2020 normals for Gainesboro, 1.8 km from Jackson County, elevation 487 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Gainesboro. 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 20 and the first fall freeze around October 22, a growing season of about 183 days.

Median at 36°F
last April 30, first October 12
Median at 32°F
last April 20, first October 22
Median at 28°F
last April 8, first October 30

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 15May 10May 6May 3Apr 30Apr 28Apr 25Apr 22Apr 17
32°FMay 6Apr 30Apr 27Apr 24Apr 20Apr 18Apr 15Apr 11Apr 7
28°FApr 23Apr 17Apr 14Apr 10Apr 8Apr 5Apr 2Mar 31Mar 24
24°FApr 11Apr 6Apr 2Mar 31Mar 28Mar 24Mar 19Mar 15Mar 6
20°FApr 1Mar 27Mar 22Mar 18Mar 14Mar 10Mar 6Feb 28Feb 22
16°FMar 22Mar 15Mar 10Mar 5Mar 1Feb 25Feb 19Feb 12Feb 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°FSep 30Oct 5Oct 8Oct 10Oct 12Oct 14Oct 17Oct 21Oct 25
32°FOct 8Oct 13Oct 16Oct 19Oct 22Oct 24Oct 27Oct 30Nov 3
28°FOct 17Oct 22Oct 25Oct 27Oct 30Nov 1Nov 3Nov 6Nov 11
24°FOct 27Nov 1Nov 3Nov 6Nov 9Nov 11Nov 15Nov 18Nov 25
20°FNov 6Nov 11Nov 14Nov 18Nov 22Nov 25Nov 29Dec 2Dec 8
16°FNov 16Nov 23Nov 27Dec 1Dec 3Dec 6Dec 11Dec 18Dec 25

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°F182176172168164161157152145
32°F201195191187183179175170163
28°F225218214209205202198192185
24°F253244238233227223218213206
20°F279270264258254248244237228
16°F313299290283278272267260251

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
4,120
Cooling degree days, base 65°F
1,357
Growing degree days, base 40°F
6,921
Growing degree days, base 45°F
5,511
Growing degree days, base 50°F
4,247
Growing degree days, base 55°F
3,135
Growing degree days, base 60°F
2,173

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January916016
February699126
March540393
April26426254
May79113500
June5270715
July0385849
August1354818
September32175593
October23330288
November542171
December809023

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 1.8 km from Jackson County. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

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Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00403370 (Gainesboro). Public domain.