Jackson County climate

Jackson County Frost Dates and Growing Season

NOAA 1991-2020 normals for Seymour 2 N, 14.6 km from Jackson County, elevation 570 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Seymour 2 N. 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 16 and the first fall freeze around October 21, a growing season of about 187 days.

Median at 36°F
last April 27, first October 12
Median at 32°F
last April 16, first October 21
Median at 28°F
last April 2, first November 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°FMay 12May 6May 3Apr 30Apr 27Apr 24Apr 22Apr 19Apr 14
32°FMay 2Apr 26Apr 23Apr 20Apr 16Apr 13Apr 10Apr 6Apr 2
28°FApr 19Apr 13Apr 8Apr 5Apr 2Mar 31Mar 29Mar 24Mar 19
24°FApr 7Apr 2Mar 31Mar 26Mar 23Mar 19Mar 16Mar 11Mar 4
20°FMar 29Mar 23Mar 19Mar 15Mar 12Mar 8Mar 4Feb 28Feb 23
16°FMar 19Mar 13Mar 10Mar 5Mar 1Feb 27Feb 22Feb 16Feb 9

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 4Oct 6Oct 9Oct 12Oct 14Oct 17Oct 20Oct 24
32°FOct 7Oct 12Oct 16Oct 19Oct 21Oct 23Oct 26Oct 29Nov 1
28°FOct 19Oct 23Oct 26Oct 29Nov 1Nov 2Nov 5Nov 8Nov 14
24°FOct 30Nov 2Nov 5Nov 8Nov 12Nov 15Nov 18Nov 24Dec 1
20°FNov 8Nov 13Nov 17Nov 22Nov 26Nov 30Dec 3Dec 7Dec 16
16°FNov 18Nov 25Dec 1Dec 3Dec 6Dec 11Dec 17Dec 22Dec 29

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°F185178174170166162158152146
32°F206199194191187182178173166
28°F233225219215211206202196190
24°F259251243238233228224219212
20°F284275268263259254249242235
16°F306299293287281276270263255

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
5,283
Cooling degree days, base 65°F
980
Growing degree days, base 40°F
5,864
Growing degree days, base 45°F
4,613
Growing degree days, base 50°F
3,496
Growing degree days, base 55°F
2,520
Growing degree days, base 60°F
1,678

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,09705
February90306
March716249
April37414168
May13277415
June17212645
July2298761
August5251711
September72109489
October33716196
November656144
December97209

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 14.6 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 USC00127935 (Seymour 2 N). Public domain.