Jackson climate

Jackson Frost Dates and Growing Season

NOAA 1991-2020 normals for Jackson Exp Stn, 2.9 km from Jackson, elevation 400 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Jackson Exp Stn. 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 2 and the first fall freeze around October 29, a growing season of about 207 days.

Median at 36°F
last April 14, first October 21
Median at 32°F
last April 2, first October 29
Median at 28°F
last March 22, first November 7

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

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 12Oct 15Oct 18Oct 21Oct 23Oct 25Oct 28Nov 1
32°FOct 16Oct 21Oct 24Oct 27Oct 29Nov 1Nov 3Nov 6Nov 11
28°FOct 27Nov 1Nov 3Nov 5Nov 7Nov 10Nov 13Nov 18Nov 24
24°FNov 3Nov 8Nov 11Nov 14Nov 17Nov 21Nov 26Dec 1Dec 9
20°FNov 10Nov 16Nov 21Nov 27Dec 1Dec 6Dec 11Dec 19Dec 28
16°FNov 21Dec 1Dec 7Dec 14Dec 22Dec 28Jan 1Jan 8Jan 19

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°F208201195192188185180176168
32°F228221215211207203200195188
28°F253246240235230225220215207
24°F279269261257252248243237229
20°F309298290284278271265258250
16°F345332324316309302296289277

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
98% 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
3,618
Cooling degree days, base 65°F
1,790
Growing degree days, base 40°F
7,726
Growing degree days, base 45°F
6,250
Growing degree days, base 50°F
4,912
Growing degree days, base 55°F
3,727
Growing degree days, base 60°F
2,686

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January839024
February652138
March45911139
April19752327
May48174591
June2353801
July0463928
August0430894
September20242672
October18759354
November4806109
December735136

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 2.9 km from Jackson. 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 USC00404561 (Jackson Exp Stn). Public domain.