Stamford climate

Stamford Frost Dates and Growing Season

NOAA 1991-2020 normals for Stamford 1, 0.5 km from Stamford, elevation 1612 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Stamford 1. 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 23 and the first fall freeze around November 11, a growing season of about 234 days.

Median at 36°F
last April 4, first November 2
Median at 32°F
last March 23, first November 11
Median at 28°F
last March 8, first November 20

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 24Apr 18Apr 12Apr 8Apr 4Apr 1Mar 28Mar 23Mar 15
32°FApr 12Apr 4Mar 31Mar 27Mar 23Mar 17Mar 13Mar 8Mar 2
28°FMar 31Mar 24Mar 17Mar 12Mar 8Mar 4Mar 1Feb 25Feb 18
24°FMar 17Mar 9Mar 4Mar 1Feb 25Feb 21Feb 15Feb 9Jan 31
20°FMar 5Feb 28Feb 21Feb 15Feb 9Feb 4Jan 30Jan 22Jan 9
16°FFeb 25Feb 16Feb 8Feb 3Jan 29Jan 21Jan 12Jan 5Dec 25

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 19Oct 25Oct 29Nov 1Nov 2Nov 5Nov 8Nov 11Nov 16
32°FOct 28Nov 2Nov 5Nov 8Nov 11Nov 14Nov 18Nov 22Nov 29
28°FNov 4Nov 9Nov 13Nov 17Nov 20Nov 25Nov 29Dec 3Dec 8
24°FNov 13Nov 20Nov 26Dec 1Dec 4Dec 8Dec 12Dec 18Dec 26
20°FNov 28Dec 5Dec 11Dec 17Dec 22Dec 28Jan 3Jan 9Jan 25
16°FDec 10Dec 19Dec 24Dec 30Jan 3Jan 8Jan 14Jan 28Feb 6

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°F236228221217212207202195188
32°F259251244239234229223217208
28°F283274268261257252246239229
24°F311302296290283277271263254
20°F350336328321314308303295283
16°F365365362352343336330320307

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
98% of years
16°F or colder
76% 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
2,784
Cooling degree days, base 65°F
2,531
Growing degree days, base 40°F
9,095
Growing degree days, base 45°F
7,496
Growing degree days, base 50°F
6,030
Growing degree days, base 55°F
4,708
Growing degree days, base 60°F
3,542

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January679140
February508379
March32221227
April12690426
May25273713
June1481930
July06171,082
August05841,049
September11338777
October112113477
November36811177
December633153

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 0.5 km from Stamford. 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 USC00418583 (Stamford 1). Public domain.