Morgan County climate

Morgan County Frost Dates and Growing Season

NOAA 1991-2020 normals for Ft Morgan, 5.1 km from Morgan County, elevation 4376 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ft Morgan. 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 6 and the first fall freeze around October 6, a growing season of about 153 days.

Median at 36°F
last May 15, first September 28
Median at 32°F
last May 6, first October 6
Median at 28°F
last April 27, first October 15

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°FMay 29May 25May 21May 18May 15May 13May 10May 7May 4
32°FMay 19May 13May 10May 8May 6May 3May 1Apr 28Apr 23
28°FMay 9May 5May 2Apr 30Apr 27Apr 23Apr 20Apr 16Apr 11
24°FMay 1Apr 25Apr 21Apr 18Apr 15Apr 11Apr 6Apr 3Mar 28
20°FApr 20Apr 14Apr 9Apr 5Apr 2Mar 30Mar 25Mar 19Mar 13
16°FApr 8Apr 2Mar 30Mar 24Mar 19Mar 14Mar 9Mar 5Mar 1

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 17Sep 21Sep 24Sep 26Sep 28Sep 30Oct 2Oct 5Oct 8
32°FSep 24Sep 29Oct 1Oct 4Oct 6Oct 8Oct 11Oct 14Oct 18
28°FOct 2Oct 6Oct 9Oct 12Oct 15Oct 17Oct 19Oct 22Oct 26
24°FOct 10Oct 14Oct 18Oct 20Oct 23Oct 25Oct 27Oct 30Nov 3
20°FOct 18Oct 23Oct 26Oct 29Nov 1Nov 2Nov 5Nov 9Nov 13
16°FOct 23Oct 29Nov 1Nov 4Nov 7Nov 11Nov 14Nov 18Nov 22

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°F151146142139135131127122115
32°F168163160156153150146141135
28°F188182178174171168164160154
24°F209202197193190186182178172
20°F235227221215211205201196188
16°F255247242235231226220213206

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
6,321
Cooling degree days, base 65°F
817
Growing degree days, base 40°F
5,094
Growing degree days, base 45°F
3,959
Growing degree days, base 50°F
2,972
Growing degree days, base 55°F
2,123
Growing degree days, base 60°F
1,404

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,17300
February97801
March761022
April508187
May25028278
June40153563
July3312773
August11241694
September11680424
October4693121
November84609
December1,16400

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 5.1 km from Morgan County. 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 USC00053038 (Ft Morgan). Public domain.