Windham climate

Windham Frost Dates and Growing Season

NOAA 1991-2020 normals for Hiram, 8.6 km from Windham, elevation 1230 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Hiram. 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 1 and the first fall freeze around October 20, a growing season of about 170 days.

Median at 36°F
last May 12, first October 7
Median at 32°F
last May 1, first October 20
Median at 28°F
last April 21, first November 1

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

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 26Sep 30Oct 2Oct 4Oct 7Oct 9Oct 12Oct 16Oct 20
32°FOct 5Oct 10Oct 14Oct 17Oct 20Oct 22Oct 25Oct 28Nov 1
28°FOct 18Oct 23Oct 27Oct 30Nov 1Nov 2Nov 5Nov 8Nov 13
24°FOct 31Nov 2Nov 5Nov 8Nov 11Nov 13Nov 17Nov 20Nov 25
20°FNov 7Nov 11Nov 15Nov 18Nov 21Nov 25Nov 28Dec 2Dec 8
16°FNov 14Nov 20Nov 25Nov 28Dec 1Dec 4Dec 7Dec 13Dec 19

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°F166159155151147143139134128
32°F188183178173170166162157150
28°F211205200196192188184179172
24°F234228223219215211208203198
20°F256249244239235231227223216
16°F278268263258254249245239233

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
6,635
Cooling degree days, base 65°F
524
Growing degree days, base 40°F
4,685
Growing degree days, base 45°F
3,577
Growing degree days, base 50°F
2,603
Growing degree days, base 55°F
1,764
Growing degree days, base 60°F
1,061

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,26501
February1,09301
March947018
April548381
May25332271
June64106493
July14181632
August23143586
September13153376
October4476121
November762020
December1,08803

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 8.6 km from Windham. 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 USC00333780 (Hiram). Public domain.