Stamford climate

Stamford Frost Dates and Growing Season

NOAA 1991-2020 normals for Lansing Manor, 13.1 km from Stamford, elevation 1100 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lansing Manor. 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 18 and the first fall freeze around October 2, a growing season of about 137 days.

Median at 36°F
last May 29, first September 23
Median at 32°F
last May 18, first October 2
Median at 28°F
last May 6, first October 12

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 12Jun 6Jun 3May 31May 29May 26May 24May 20May 14
32°FJun 1May 27May 24May 21May 18May 14May 11May 7May 1
28°FMay 20May 15May 12May 9May 6May 3Apr 30Apr 28Apr 23
24°FMay 10May 4May 1Apr 28Apr 24Apr 21Apr 18Apr 14Apr 8
20°FApr 26Apr 20Apr 17Apr 14Apr 11Apr 8Apr 5Apr 2Mar 30
16°FApr 14Apr 9Apr 6Apr 3Apr 1Mar 31Mar 28Mar 23Mar 19

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 8Sep 13Sep 17Sep 20Sep 23Sep 26Sep 28Oct 1Oct 4
32°FSep 19Sep 24Sep 28Oct 1Oct 2Oct 4Oct 7Oct 10Oct 14
28°FOct 1Oct 3Oct 7Oct 10Oct 12Oct 15Oct 19Oct 24Nov 1
24°FOct 10Oct 14Oct 18Oct 22Oct 26Oct 31Nov 3Nov 6Nov 11
20°FOct 22Oct 29Nov 1Nov 4Nov 7Nov 11Nov 13Nov 17Nov 23
16°FNov 3Nov 9Nov 12Nov 16Nov 19Nov 22Nov 25Nov 29Dec 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°F13613012512111711310910497
32°F157151146142137133129125117
28°F181174169164160156152146139
24°F205198193189185181176171164
20°F230222217213209205200194187
16°F252244238233229226221217210

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
7,314
Cooling degree days, base 65°F
370
Growing degree days, base 40°F
4,122
Growing degree days, base 45°F
3,086
Growing degree days, base 50°F
2,190
Growing degree days, base 55°F
1,430
Growing degree days, base 60°F
816

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,33701
February1,15500
March1,04305
April652244
May32117204
June10367416
July26136575
August42107530
September18238315
October515284
November806014
December1,13202

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 13.1 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 USC00304575 (Lansing Manor). Public domain.