Pomfret climate

Pomfret Frost Dates and Growing Season

NOAA 1991-2020 normals for Quantico Mcas, 25 km from Pomfret, elevation 10 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Quantico Mcas. 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 March 28 and the first fall freeze around November 8, a growing season of about 226 days.

Median at 36°F
last April 8, first October 29
Median at 32°F
last March 28, first November 8
Median at 28°F
last March 17, first November 22

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°FApr 25Apr 19Apr 15Apr 11Apr 8Apr 6Apr 3Mar 31Mar 27
32°FApr 8Apr 5Apr 2Mar 31Mar 28Mar 26Mar 22Mar 19Mar 14
28°FMar 30Mar 26Mar 22Mar 19Mar 17Mar 14Mar 10Mar 6Feb 28
24°FMar 21Mar 17Mar 14Mar 9Mar 6Mar 3Feb 27Feb 22Feb 13
20°FMar 14Mar 7Mar 2Feb 27Feb 23Feb 17Feb 11Feb 5Jan 30
16°FMar 3Feb 24Feb 18Feb 12Feb 6Feb 2Jan 29Jan 22Jan 12

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°FOct 15Oct 20Oct 24Oct 27Oct 29Oct 31Nov 2Nov 5Nov 10
32°FOct 28Nov 1Nov 3Nov 6Nov 8Nov 11Nov 14Nov 18Nov 25
28°FNov 7Nov 12Nov 15Nov 18Nov 22Nov 26Dec 1Dec 4Dec 10
24°FNov 19Nov 25Nov 30Dec 3Dec 7Dec 12Dec 18Dec 23Dec 29
20°FDec 4Dec 9Dec 16Dec 22Dec 25Dec 29Jan 2Jan 8Jan 17
16°FDec 15Dec 25Dec 30Jan 3Jan 8Jan 14Jan 18Jan 24Feb 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°F222214210206202199193188181
32°F248241235230226223219214208
28°F275268262256251247242236231
24°F306297289283277272267260253
20°F331322315308303298291286277
16°F363349340334329322316308300

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
91% 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
4,003
Cooling degree days, base 65°F
1,512
Growing degree days, base 40°F
7,059
Growing degree days, base 45°F
5,635
Growing degree days, base 50°F
4,379
Growing degree days, base 55°F
3,270
Growing degree days, base 60°F
2,315

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January88209
February718017
March571373
April25630249
May79114501
June6300744
July0445910
August0389854
September22196624
October21132299
November495279
December763020

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 25 km from Pomfret. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USW00013773 (Quantico Mcas). Public domain.