Pittsfield climate

Pittsfield Frost Dates and Growing Season

NOAA 1991-2020 normals for Green Bay WFO, 15.4 km from Pittsfield, elevation 682 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Green Bay WFO. 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 11, a growing season of about 160 days.

Median at 36°F
last May 14, first September 30
Median at 32°F
last May 1, first October 11
Median at 28°F
last April 20, first October 25

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 29May 25May 21May 17May 14May 11May 8May 4Apr 30
32°FMay 16May 12May 7May 4May 1Apr 29Apr 27Apr 23Apr 19
28°FMay 4Apr 30Apr 26Apr 23Apr 20Apr 16Apr 13Apr 10Apr 6
24°FApr 21Apr 16Apr 13Apr 10Apr 7Apr 4Apr 2Mar 31Mar 24
20°FApr 12Apr 7Apr 4Apr 2Mar 31Mar 28Mar 24Mar 20Mar 15
16°FApr 5Mar 31Mar 29Mar 25Mar 22Mar 19Mar 16Mar 13Mar 9

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 18Sep 21Sep 24Sep 27Sep 30Oct 2Oct 5Oct 8Oct 13
32°FSep 26Oct 1Oct 5Oct 8Oct 11Oct 14Oct 17Oct 20Oct 26
28°FOct 10Oct 15Oct 18Oct 22Oct 25Oct 28Oct 31Nov 2Nov 6
24°FOct 24Oct 29Nov 1Nov 3Nov 5Nov 7Nov 11Nov 14Nov 19
20°FNov 2Nov 6Nov 9Nov 12Nov 14Nov 17Nov 20Nov 24Nov 28
16°FNov 9Nov 14Nov 17Nov 20Nov 23Nov 25Nov 28Dec 2Dec 8

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°F158152146142137133129124118
32°F182174169164160157153147140
28°F206199194190186181177172165
24°F230224218215211207203199191
20°F250243237233230226222217211
16°F266259254250246242238234228

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
7,670
Cooling degree days, base 65°F
464
Growing degree days, base 40°F
4,244
Growing degree days, base 45°F
3,232
Growing degree days, base 50°F
2,353
Growing degree days, base 55°F
1,592
Growing degree days, base 60°F
953

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,47200
February1,23800
March1,03919
April638140
May30219219
June7389467
July15176626
August28134570
September17041330
October521484
November89406
December1,28000

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 15.4 km from Pittsfield. 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 USC00473268 (Green Bay WFO). Public domain.