Ascutney climate

Ascutney Frost Dates and Growing Season

NOAA 1991-2020 normals for N Springfield Lake, 11 km from Ascutney, elevation 560 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for N Springfield Lake. 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 May 9 and the first fall freeze around October 2, a growing season of about 146 days.

Median at 36°F
last May 21, first September 24
Median at 32°F
last May 9, first October 2
Median at 28°F
last April 27, first October 14

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°FJun 4May 31May 28May 24May 21May 19May 16May 12May 7
32°FMay 22May 18May 15May 12May 9May 6May 3Apr 30Apr 26
28°FMay 10May 5May 2Apr 30Apr 27Apr 24Apr 22Apr 19Apr 14
24°FApr 27Apr 21Apr 18Apr 16Apr 13Apr 11Apr 8Apr 5Apr 2
20°FApr 16Apr 10Apr 7Apr 5Apr 4Apr 2Mar 31Mar 28Mar 21
16°FApr 6Apr 3Apr 2Mar 31Mar 28Mar 24Mar 20Mar 16Mar 13

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 9Sep 14Sep 17Sep 21Sep 24Sep 26Sep 29Oct 1Oct 5
32°FSep 21Sep 26Sep 29Oct 1Oct 2Oct 5Oct 8Oct 12Oct 16
28°FOct 1Oct 3Oct 7Oct 10Oct 14Oct 17Oct 20Oct 25Oct 31
24°FOct 10Oct 17Oct 20Oct 25Oct 28Nov 1Nov 3Nov 7Nov 12
20°FOct 24Oct 30Nov 2Nov 6Nov 9Nov 12Nov 15Nov 20Nov 25
16°FNov 8Nov 12Nov 15Nov 18Nov 22Nov 26Nov 28Dec 1Dec 7

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°F142136131126123120115110103
32°F166158153150146142138133126
28°F191183177173169163159155147
24°F214208203199195191185180173
20°F238231226222218215211205199
16°F259252247242239234231227221

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
7,524
Cooling degree days, base 65°F
403
Growing degree days, base 40°F
4,122
Growing degree days, base 45°F
3,121
Growing degree days, base 50°F
2,243
Growing degree days, base 55°F
1,486
Growing degree days, base 60°F
866

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,42000
February1,20400
March1,05604
April651138
May29612212
June8570436
July13163615
August35116546
September18140316
October535271
November85105
December1,20000

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 11 km from Ascutney. 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 USC00435982 (N Springfield Lake). Public domain.