Jackson climate

Jackson Frost Dates and Growing Season

NOAA 1991-2020 normals for Jackson, 0.5 km from Jackson, elevation 903 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 30 and the first fall freeze around October 15, a growing season of about 167 days.

Median at 36°F
last May 12, first October 4
Median at 32°F
last April 30, first October 15
Median at 28°F
last April 17, first October 27

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

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°F164157152148145141137133126
32°F187179175171167162158153147
28°F211204199195191187183177170
24°F236229223219215211208203197
20°F258250245240235231227222215
16°F275267262258253249245239232

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
7,178
Cooling degree days, base 65°F
558
Growing degree days, base 40°F
4,522
Growing degree days, base 45°F
3,465
Growing degree days, base 50°F
2,545
Growing degree days, base 55°F
1,747
Growing degree days, base 60°F
1,080

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,38700
February1,16501
March985114
April611144
May29323229
June66105490
July14204655
August20158603
September14361373
October4615119
November836017
December1,19800

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 USC00473930 (Jackson). Public domain.