Jamesport climate

Jamesport Frost Dates and Growing Season

NOAA 1991-2020 normals for Gallatin 1W, 16.2 km from Jamesport, elevation 921 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Gallatin 1W. 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 19 and the first fall freeze around October 21, a growing season of about 184 days.

Median at 36°F
last April 30, first October 9
Median at 32°F
last April 19, first October 21
Median at 28°F
last April 7, first October 30

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 14May 8May 4May 2Apr 30Apr 27Apr 24Apr 20Apr 15
32°FMay 4Apr 30Apr 27Apr 23Apr 19Apr 16Apr 12Apr 8Apr 5
28°FApr 23Apr 18Apr 14Apr 10Apr 7Apr 5Apr 2Mar 29Mar 22
24°FApr 13Apr 8Apr 5Apr 1Mar 30Mar 26Mar 22Mar 17Mar 12
20°FApr 5Mar 31Mar 26Mar 21Mar 18Mar 14Mar 11Mar 7Mar 2
16°FMar 28Mar 21Mar 16Mar 13Mar 10Mar 6Mar 3Feb 28Feb 24

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

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°F182176171167163159155150143
32°F202196192188184179175169162
28°F224217212208203200197192185
24°F245238231226222218214209202
20°F264257251246241237231226219
16°F285276270265259255249244237

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
5,883
Cooling degree days, base 65°F
1,031
Growing degree days, base 40°F
5,719
Growing degree days, base 45°F
4,525
Growing degree days, base 50°F
3,461
Growing degree days, base 55°F
2,524
Growing degree days, base 60°F
1,711

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,24301
February99405
March754244
April4139147
May15665383
June14218654
July2335798
August5278738
September88109473
October37015185
November737033
December1,10802

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 16.2 km from Jamesport. 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 USC00233102 (Gallatin 1W). Public domain.