Morrill climate

Morrill Frost Dates and Growing Season

NOAA 1991-2020 normals for Torrington Muni AP, 21.9 km from Morrill, elevation 4205 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Torrington Muni 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 May 11 and the first fall freeze around September 29, a growing season of about 139 days.

Median at 36°F
last May 22, first September 21
Median at 32°F
last May 11, first September 29
Median at 28°F
last April 30, first October 8

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 5Jun 1May 29May 25May 22May 19May 17May 13May 9
32°FMay 26May 20May 17May 14May 11May 8May 5May 3Apr 30
28°FMay 13May 8May 5May 2Apr 30Apr 28Apr 25Apr 21Apr 16
24°FMay 4Apr 30Apr 26Apr 22Apr 19Apr 16Apr 12Apr 8Apr 3
20°FApr 23Apr 18Apr 14Apr 11Apr 7Apr 4Mar 31Mar 27Mar 20
16°FApr 15Apr 9Apr 5Mar 31Mar 27Mar 23Mar 18Mar 14Mar 8

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 16Sep 19Sep 21Sep 23Sep 25Sep 28Oct 2
32°FSep 16Sep 21Sep 24Sep 27Sep 29Oct 1Oct 4Oct 7Oct 11
28°FSep 24Sep 29Oct 2Oct 5Oct 8Oct 11Oct 14Oct 17Oct 21
24°FOct 2Oct 8Oct 12Oct 15Oct 17Oct 20Oct 23Oct 27Oct 31
20°FOct 12Oct 16Oct 20Oct 23Oct 27Oct 30Nov 1Nov 5Nov 10
16°FOct 19Oct 24Oct 27Oct 31Nov 3Nov 6Nov 9Nov 13Nov 19

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°F138132128124121117112107100
32°F158152147143139136132128119
28°F179172167163160156151146140
24°F201195190185181176171167161
20°F223215210205201197192187178
16°F244237231225220215209203195

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
6,480
Cooling degree days, base 65°F
725
Growing degree days, base 40°F
4,804
Growing degree days, base 45°F
3,682
Growing degree days, base 50°F
2,727
Growing degree days, base 55°F
1,926
Growing degree days, base 60°F
1,262

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,12401
February96302
March800017
April559158
May29718227
June62129519
July4291751
August15225676
September14460378
October522190
November85508
December1,13601

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 21.9 km from Morrill. 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 USW00094053 (Torrington Muni AP). Public domain.