Fairmont climate

Fairmont Frost Dates and Growing Season

NOAA 1991-2020 normals for Fairmont, 0.9 km from Fairmont, elevation 1640 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Fairmont. 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 25 and the first fall freeze around October 14, a growing season of about 170 days.

Median at 36°F
last May 4, first October 4
Median at 32°F
last April 25, first October 14
Median at 28°F
last April 15, first October 22

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 15May 12May 8May 6May 4May 2Apr 30Apr 27Apr 22
32°FMay 7May 3May 1Apr 29Apr 25Apr 22Apr 19Apr 15Apr 10
28°FApr 30Apr 25Apr 21Apr 18Apr 15Apr 12Apr 9Apr 6Apr 1
24°FApr 20Apr 15Apr 11Apr 8Apr 5Apr 2Mar 31Mar 26Mar 19
20°FApr 11Apr 6Apr 2Mar 31Mar 27Mar 23Mar 19Mar 14Mar 9
16°FApr 5Mar 31Mar 26Mar 21Mar 17Mar 14Mar 9Mar 5Mar 1

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 21Sep 26Sep 29Oct 1Oct 4Oct 7Oct 10Oct 13Oct 17
32°FSep 29Oct 3Oct 7Oct 11Oct 14Oct 17Oct 19Oct 21Oct 25
28°FOct 5Oct 12Oct 16Oct 19Oct 22Oct 23Oct 26Oct 29Nov 3
24°FOct 16Oct 21Oct 24Oct 28Oct 31Nov 2Nov 5Nov 8Nov 14
20°FOct 24Oct 31Nov 2Nov 5Nov 8Nov 11Nov 14Nov 19Nov 26
16°FOct 31Nov 5Nov 9Nov 12Nov 15Nov 20Nov 24Nov 28Dec 4

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°F170163159155152149146140135
32°F190183179175170166163157150
28°F209202198193189185181175169
24°F228221216212207204199194188
20°F248239234229225221217212204
16°F266259253247242238232226219

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
6,252
Cooling degree days, base 65°F
985
Growing degree days, base 40°F
5,491
Growing degree days, base 45°F
4,335
Growing degree days, base 50°F
3,304
Growing degree days, base 55°F
2,399
Growing degree days, base 60°F
1,623

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,27700
February1,03703
March803032
April4645114
May18059356
June21216645
July2325787
August9260716
September98107463
October40613166
November798022
December1,15601

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 0.9 km from Fairmont. 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 USC00252840 (Fairmont). Public domain.