Norridgewock climate

Norridgewock Frost Dates and Growing Season

NOAA 1991-2020 normals for Madison, 12.2 km from Norridgewock, elevation 220 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Madison. 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 8 and the first fall freeze around October 5, a growing season of about 149 days.

Median at 36°F
last May 19, first September 25
Median at 32°F
last May 8, first October 5
Median at 28°F
last April 28, first October 18

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 31May 27May 24May 22May 19May 17May 14May 11May 7
32°FMay 20May 16May 13May 11May 8May 6May 4May 1Apr 28
28°FMay 8May 5May 2Apr 30Apr 28Apr 25Apr 23Apr 20Apr 16
24°FApr 27Apr 23Apr 20Apr 18Apr 15Apr 12Apr 9Apr 7Apr 4
20°FApr 18Apr 13Apr 9Apr 7Apr 5Apr 3Apr 2Mar 31Mar 27
16°FApr 7Apr 4Apr 2Apr 1Mar 31Mar 28Mar 24Mar 20Mar 15

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

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°F143138133129126123120115109
32°F167160156152149145142137131
28°F192185180177173170166162155
24°F215210206202199195191186180
20°F238231227223220217212208202
16°F254249244241238235231227222

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
8,217
Cooling degree days, base 65°F
291
Growing degree days, base 40°F
3,727
Growing degree days, base 45°F
2,769
Growing degree days, base 50°F
1,941
Growing degree days, base 55°F
1,244
Growing degree days, base 60°F
685

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,51300
February1,32200
March1,15001
April728014
May3806142
June12247377
July25123563
August4292515
September21124274
October567152
November89104
December1,26800

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 12.2 km from Norridgewock. 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 USC00174927 (Madison). Public domain.