Torrington climate

Torrington Frost Dates and Growing Season

NOAA 1991-2020 normals for Torrington Exp Farm, 3.8 km from Torrington, elevation 4098 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Torrington Exp Farm. 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 14 and the first fall freeze around September 24, a growing season of about 130 days.

Median at 36°F
last May 26, first September 15
Median at 32°F
last May 14, first September 24
Median at 28°F
last May 3, first October 3

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 10Jun 5Jun 1May 29May 26May 23May 21May 17May 13
32°FMay 28May 23May 19May 16May 14May 11May 9May 6May 2
28°FMay 17May 12May 8May 6May 3May 1Apr 29Apr 26Apr 21
24°FMay 7May 2Apr 30Apr 28Apr 25Apr 21Apr 18Apr 15Apr 10
20°FApr 27Apr 22Apr 18Apr 15Apr 12Apr 9Apr 5Apr 2Mar 28
16°FApr 17Apr 11Apr 7Apr 3Mar 31Mar 28Mar 23Mar 18Mar 11

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 2Sep 7Sep 10Sep 13Sep 15Sep 18Sep 20Sep 23Sep 25
32°FSep 10Sep 15Sep 19Sep 21Sep 24Sep 26Sep 28Oct 1Oct 5
28°FSep 20Sep 24Sep 27Sep 30Oct 3Oct 5Oct 8Oct 12Oct 17
24°FSep 29Oct 3Oct 7Oct 10Oct 13Oct 16Oct 18Oct 21Oct 26
20°FOct 8Oct 14Oct 17Oct 20Oct 22Oct 24Oct 27Oct 31Nov 3
16°FOct 17Oct 21Oct 24Oct 27Oct 30Nov 1Nov 4Nov 8Nov 13

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°F12912211811411110710410094
32°F148143138134130127122118111
28°F170164159155152148144139131
24°F189184178175171167163159151
20°F213205200195191187183179171
16°F235228221217212207202197190

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
6,713
Cooling degree days, base 65°F
644
Growing degree days, base 40°F
4,646
Growing degree days, base 45°F
3,544
Growing degree days, base 50°F
2,606
Growing degree days, base 55°F
1,817
Growing degree days, base 60°F
1,167

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,16600
February99801
March836014
April567059
May29615226
June69114497
July9260716
August17204653
September16149354
October538178
November87608
December1,18100

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 3.8 km from Torrington. 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 USC00488995 (Torrington Exp Farm). Public domain.