Sutton-Alpine climate

Sutton-Alpine Frost Dates and Growing Season

NOAA 1991-2020 normals for Sutton 1 W, 0.9 km from Sutton-Alpine, elevation 550 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sutton 1 W. 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 June 1 and the first fall freeze around September 6, a growing season of about 98 days.

Median at 32°F
last June 1, first September 6
Median at 28°F
last May 18, first September 21

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°F–––––––––
32°FJun 13Jun 9Jun 5Jun 3Jun 1May 31May 28May 25May 20
28°FMay 31May 27May 24May 21May 18May 15May 12May 9May 3
24°FMay 15May 10May 7May 4May 1Apr 29Apr 26Apr 22Apr 17
20°FMay 1Apr 26Apr 22Apr 19Apr 15Apr 12Apr 9Apr 6Apr 3
16°FApr 21Apr 16Apr 11Apr 8Apr 5Apr 3Apr 1Mar 30Mar 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°F–––––––––
32°FAug 24Aug 30Sep 1Sep 4Sep 6Sep 10Sep 13Sep 16Sep 20
28°FSep 5Sep 11Sep 15Sep 18Sep 21Sep 24Sep 26Sep 29Oct 3
24°FSep 17Sep 23Sep 26Sep 29Oct 1Oct 4Oct 6Oct 11Oct 16
20°FSep 28Oct 2Oct 5Oct 8Oct 11Oct 15Oct 18Oct 22Oct 27
16°FOct 5Oct 10Oct 15Oct 18Oct 21Oct 25Oct 28Nov 1Nov 6

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°F898276716660554941
32°F1151091061029894908578
28°F144138134129125122117113107
24°F173167161157153149145140133
20°F200193188184179175171165159
16°F217211206202198194190185178

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
10,388
Cooling degree days, base 65°F
3
Growing degree days, base 40°F
1,986
Growing degree days, base 45°F
1,216
Growing degree days, base 50°F
611
Growing degree days, base 55°F
211
Growing degree days, base 60°F
39

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,52700
February1,23500
March1,19700
April82102
May547030
June3141146
July2252242
August3040166
September542024
October91901
November1,28400
December1,47400

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 Sutton-Alpine. 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 USC00508915 (Sutton 1 W). Public domain.