Woonsocket climate

Woonsocket Frost Dates and Growing Season

NOAA 1991-2020 normals for Forestburg 4 Nne, 15.5 km from Woonsocket, elevation 1277 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Forestburg 4 Nne. 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 September 28, a growing season of about 140 days.

Median at 36°F
last May 19, first September 19
Median at 32°F
last May 9, first September 28
Median at 28°F
last April 30, first October 6

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 2May 29May 26May 22May 19May 16May 13May 10May 6
32°FMay 24May 18May 14May 12May 9May 6May 3May 1Apr 27
28°FMay 13May 8May 5May 2Apr 30Apr 27Apr 24Apr 20Apr 15
24°FMay 5May 1Apr 27Apr 24Apr 20Apr 17Apr 14Apr 10Apr 6
20°FApr 28Apr 21Apr 17Apr 14Apr 11Apr 8Apr 6Apr 3Mar 29
16°FApr 18Apr 13Apr 9Apr 5Apr 3Mar 31Mar 28Mar 23Mar 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 6Sep 11Sep 14Sep 17Sep 19Sep 22Sep 25Sep 27Oct 1
32°FSep 14Sep 19Sep 23Sep 26Sep 28Oct 1Oct 3Oct 5Oct 10
28°FSep 23Sep 27Oct 1Oct 3Oct 6Oct 9Oct 12Oct 15Oct 19
24°FOct 1Oct 5Oct 10Oct 13Oct 16Oct 18Oct 21Oct 24Oct 28
20°FOct 11Oct 16Oct 20Oct 23Oct 25Oct 28Oct 30Nov 2Nov 5
16°FOct 20Oct 25Oct 29Oct 31Nov 2Nov 4Nov 7Nov 11Nov 16

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°F140134129125122118114109103
32°F157151147143140136133128121
28°F176170165161158154150145138
24°F195189184181176171167162155
20°F214208202198194190186181173
16°F234226220215211207203198192

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
7,755
Cooling degree days, base 65°F
671
Growing degree days, base 40°F
4,635
Growing degree days, base 45°F
3,605
Growing degree days, base 50°F
2,689
Growing degree days, base 55°F
1,888
Growing degree days, base 60°F
1,211

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,53400
February1,25300
March1,003010
April581266
May26028263
June48132534
July10250705
August24185626
September15071380
October538596
November97407
December1,38100

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 15.5 km from Woonsocket. 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 USC00393029 (Forestburg 4 Nne). Public domain.