Windsor County climate

Windsor County Frost Dates and Growing Season

NOAA 1991-2020 normals for Woodstock, 8.5 km from Windsor County, elevation 600 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Woodstock. 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 13 and the first fall freeze around October 1, a growing season of about 141 days.

Median at 36°F
last May 24, first September 23
Median at 32°F
last May 13, first October 1
Median at 28°F
last April 30, first October 12

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 6Jun 3May 31May 28May 24May 21May 18May 15May 10
32°FMay 27May 22May 19May 16May 13May 9May 6May 2Apr 29
28°FMay 15May 9May 5May 2Apr 30Apr 27Apr 25Apr 22Apr 18
24°FApr 29Apr 25Apr 21Apr 19Apr 16Apr 13Apr 10Apr 7Apr 3
20°FApr 16Apr 12Apr 9Apr 6Apr 5Apr 3Apr 1Mar 30Mar 24
16°FApr 7Apr 4Apr 2Mar 31Mar 30Mar 27Mar 23Mar 20Mar 16

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 20Sep 23Sep 25Sep 27Sep 30Oct 3
32°FSep 20Sep 24Sep 27Sep 30Oct 1Oct 4Oct 6Oct 10Oct 15
28°FOct 1Oct 3Oct 6Oct 9Oct 12Oct 14Oct 18Oct 23Oct 31
24°FOct 10Oct 14Oct 17Oct 20Oct 25Oct 28Nov 1Nov 4Nov 9
20°FOct 22Oct 28Oct 31Nov 3Nov 6Nov 9Nov 12Nov 17Nov 23
16°FNov 4Nov 9Nov 13Nov 16Nov 19Nov 22Nov 26Nov 29Dec 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°F139132128125121117113108101
32°F162155150145141137133129123
28°F186178173168164160156151143
24°F210203198194191186182177170
20°F233227221218214210206202196
16°F252246241238234231227222217

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
7,703
Cooling degree days, base 65°F
410
Growing degree days, base 40°F
4,088
Growing degree days, base 45°F
3,096
Growing degree days, base 50°F
2,230
Growing degree days, base 55°F
1,483
Growing degree days, base 60°F
868

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,44400
February1,24200
March1,09003
April656240
May31315204
June8679444
July17156604
August35120550
September18338313
October548166
November86306
December1,22800

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 8.5 km from Windsor County. 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 USC00439984 (Woodstock). Public domain.