Seaboard climate

Seaboard Frost Dates and Growing Season

NOAA 1991-2020 normals for Jackson, 10.5 km from Seaboard, elevation 123 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 5 and the first fall freeze around November 1, a growing season of about 211 days.

Median at 36°F
last April 18, first October 25
Median at 32°F
last April 5, first November 1
Median at 28°F
last March 26, first November 13

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 1Apr 27Apr 23Apr 21Apr 18Apr 16Apr 13Apr 9Apr 3
32°FApr 18Apr 15Apr 11Apr 8Apr 5Apr 3Apr 1Mar 28Mar 22
28°FApr 8Apr 4Apr 2Mar 30Mar 26Mar 22Mar 19Mar 15Mar 9
24°FMar 29Mar 23Mar 19Mar 15Mar 11Mar 7Mar 3Feb 27Feb 18
20°FMar 18Mar 11Mar 6Mar 1Feb 26Feb 20Feb 14Feb 6Jan 30
16°FMar 5Feb 28Feb 20Feb 11Feb 5Jan 31Jan 28Jan 21Jan 11

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 12Oct 15Oct 19Oct 22Oct 25Oct 27Oct 30Nov 1Nov 5
32°FOct 20Oct 25Oct 28Oct 31Nov 1Nov 4Nov 7Nov 10Nov 17
28°FOct 31Nov 4Nov 6Nov 10Nov 13Nov 17Nov 20Nov 25Dec 1
24°FNov 9Nov 15Nov 19Nov 23Nov 28Dec 1Dec 6Dec 13Dec 26
20°FNov 24Dec 1Dec 6Dec 12Dec 18Dec 25Jan 1Jan 6Jan 15
16°FDec 8Dec 19Dec 27Jan 1Jan 5Jan 10Jan 14Jan 21Jan 31

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°F208201196193189185181176172
32°F231223219214211207203198191
28°F257250244239234229225220213
24°F293282274268262256250244236
20°F327316308302296291284276263
16°F360347339333328319312304297

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
91% 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
3,665
Cooling degree days, base 65°F
1,495
Growing degree days, base 40°F
7,281
Growing degree days, base 45°F
5,799
Growing degree days, base 50°F
4,479
Growing degree days, base 55°F
3,322
Growing degree days, base 60°F
2,329

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January792024
February647029
March5144101
April24133267
May77119508
June6297741
July0423888
August0371835
September21203631
October20439314
November4644103
December697138

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 10.5 km from Seaboard. 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 USC00314456 (Jackson). Public domain.