Trumbull climate

Trumbull Frost Dates and Growing Season

NOAA 1991-2020 normals for Bridgeport Sikorsky Mem AP, 11.2 km from Trumbull, elevation 5 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Bridgeport Sikorsky Mem AP. 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 April 5 and the first fall freeze around November 6, a growing season of about 216 days.

Median at 36°F
last April 16, first October 26
Median at 32°F
last April 5, first November 6
Median at 28°F
last March 26, first November 19

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 29Apr 24Apr 21Apr 19Apr 16Apr 14Apr 12Apr 9Apr 6
32°FApr 17Apr 13Apr 9Apr 7Apr 5Apr 3Apr 1Mar 30Mar 25
28°FApr 6Apr 3Mar 31Mar 29Mar 26Mar 23Mar 21Mar 16Mar 11
24°FMar 30Mar 25Mar 21Mar 18Mar 15Mar 12Mar 9Mar 6Feb 28
20°FMar 21Mar 17Mar 13Mar 9Mar 7Mar 4Feb 28Feb 24Feb 17
16°FMar 12Mar 7Mar 3Feb 28Feb 24Feb 19Feb 15Feb 10Feb 4

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 11Oct 17Oct 20Oct 23Oct 26Oct 29Nov 1Nov 4Nov 8
32°FOct 25Oct 30Nov 1Nov 4Nov 6Nov 9Nov 12Nov 16Nov 20
28°FNov 6Nov 11Nov 14Nov 16Nov 19Nov 22Nov 27Dec 1Dec 5
24°FNov 15Nov 21Nov 25Nov 29Dec 1Dec 4Dec 7Dec 11Dec 17
20°FNov 28Dec 3Dec 6Dec 10Dec 14Dec 18Dec 22Dec 26Jan 1
16°FDec 6Dec 15Dec 21Dec 25Dec 29Jan 1Jan 5Jan 9Jan 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°F210205201197194190185181175
32°F234228223220216213209205198
28°F259251246242238234231226221
24°F281273267263259255251246240
20°F304297291287282277273266259
16°F332322316309304300295289280

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
5,140
Cooling degree days, base 65°F
955
Growing degree days, base 40°F
5,727
Growing degree days, base 45°F
4,452
Growing degree days, base 50°F
3,347
Growing degree days, base 55°F
2,399
Growing degree days, base 60°F
1,602

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,04201
February89301
March78009
April452283
May18229314
June25163588
July0330795
August1294758
September45123528
October28214222
November570044
December86805

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 11.2 km from Trumbull. 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 USW00094702 (Bridgeport Sikorsky Mem AP). Public domain.