Coalville climate

Coalville Frost Dates and Growing Season

NOAA 1991-2020 normals for Coalville, 0.5 km from Coalville, elevation 5550 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Coalville. 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 June 7 and the first fall freeze around September 12, a growing season of about 95 days.

Median at 32°F
last June 7, first September 12
Median at 28°F
last May 21, first September 25

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°F–––––––––
32°FJun 25Jun 19Jun 15Jun 11Jun 7Jun 4May 31May 28May 21
28°FJun 9Jun 2May 29May 24May 21May 17May 13May 9May 5
24°FMay 20May 13May 9May 5May 3May 1Apr 27Apr 23Apr 19
20°FMay 4Apr 28Apr 23Apr 19Apr 15Apr 13Apr 10Apr 5Mar 31
16°FApr 15Apr 10Apr 6Apr 3Mar 30Mar 26Mar 19Mar 13Mar 6

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°F–––––––––
32°FAug 28Sep 2Sep 5Sep 9Sep 12Sep 15Sep 18Sep 21Sep 25
28°FSep 9Sep 15Sep 19Sep 22Sep 25Sep 27Sep 30Oct 3Oct 6
24°FSep 23Sep 28Oct 1Oct 3Oct 6Oct 8Oct 12Oct 16Oct 23
20°FOct 4Oct 9Oct 14Oct 18Oct 21Oct 24Oct 26Oct 30Nov 4
16°FOct 18Oct 22Oct 25Oct 28Nov 1Nov 3Nov 6Nov 10Nov 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°F888175716662565040
32°F118111104999589857969
28°F14714013513012512111510999
24°F176169162158154150146140133
20°F207199194190184180175169160
16°F244233227221215210205200192

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
6,959
Cooling degree days, base 65°F
271
Growing degree days, base 40°F
3,919
Growing degree days, base 45°F
2,836
Growing degree days, base 50°F
1,939
Growing degree days, base 55°F
1,221
Growing degree days, base 60°F
665

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,20400
February98100
March78904
April593028
May3772137
June13328348
July22129572
August28102539
September20710263
October539046
November87503
December1,21200

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 Coalville. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USW00024120 (Coalville). Public domain.