Jackson climate

Jackson Frost Dates and Growing Season

NOAA 1991-2020 normals for Jackson, 0.5 km from Jackson, elevation 440 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Jackson. 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 7 and the first fall freeze around October 29, a growing season of about 202 days.

Median at 36°F
last April 19, first October 19
Median at 32°F
last April 7, first October 29
Median at 28°F
last March 29, first November 5

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 3Apr 29Apr 25Apr 22Apr 19Apr 16Apr 13Apr 9Apr 4
32°FApr 22Apr 17Apr 14Apr 11Apr 7Apr 4Apr 1Mar 29Mar 24
28°FApr 13Apr 8Apr 4Apr 1Mar 29Mar 26Mar 23Mar 18Mar 10
24°FApr 3Mar 29Mar 25Mar 21Mar 18Mar 14Mar 11Mar 6Feb 28
20°FMar 23Mar 17Mar 14Mar 9Mar 6Mar 4Mar 1Feb 25Feb 18
16°FMar 15Mar 8Mar 5Mar 2Feb 28Feb 23Feb 17Feb 11Feb 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°FOct 7Oct 11Oct 14Oct 17Oct 19Oct 21Oct 24Oct 27Oct 30
32°FOct 16Oct 20Oct 23Oct 26Oct 29Oct 31Nov 1Nov 4Nov 9
28°FOct 25Oct 31Nov 1Nov 3Nov 5Nov 8Nov 12Nov 16Nov 23
24°FNov 3Nov 6Nov 10Nov 13Nov 17Nov 21Nov 26Dec 1Dec 5
20°FNov 8Nov 14Nov 19Nov 24Nov 29Dec 1Dec 6Dec 11Dec 19
16°FNov 16Nov 26Dec 1Dec 5Dec 9Dec 14Dec 19Dec 25Jan 1

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°F199194190186182178174169163
32°F223215210206202199195191184
28°F246237232227222218214209202
24°F268259254249245240235230223
20°F294284277272266260254249241
16°F318307300294288282276270260

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
4,499
Cooling degree days, base 65°F
1,592
Growing degree days, base 40°F
6,971
Growing degree days, base 45°F
5,624
Growing degree days, base 50°F
4,418
Growing degree days, base 55°F
3,345
Growing degree days, base 60°F
2,405

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,00907
February801013
March592375
April26227252
May70141537
June3337784
July0451916
August0403868
September34192608
October24437285
November593262
December891012

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 0.5 km from Jackson. 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 USC00234226 (Jackson). Public domain.