Fort Duchesne climate

Fort Duchesne Frost Dates and Growing Season

NOAA 1991-2020 normals for Ft Duchesne, 0.7 km from Fort Duchesne, elevation 5052 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ft Duchesne. 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 19 and the first fall freeze around October 2, a growing season of about 135 days.

Median at 36°F
last June 3, first September 22
Median at 32°F
last May 19, first October 2
Median at 28°F
last May 3, 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°FJul 3Jun 20Jun 12Jun 6Jun 3May 31May 27May 22May 16
32°FJun 15Jun 4May 31May 24May 19May 14May 10May 5May 1
28°FMay 31May 19May 13May 7May 3Apr 30Apr 27Apr 23Apr 18
24°FMay 14May 3Apr 28Apr 23Apr 19Apr 15Apr 11Apr 6Apr 2
20°FApr 24Apr 16Apr 10Apr 4Apr 1Mar 29Mar 24Mar 18Mar 11
16°FApr 9Mar 31Mar 26Mar 20Mar 15Mar 12Mar 8Mar 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 6Sep 13Sep 17Sep 20Sep 22Sep 25Sep 27Sep 30Oct 4
32°FSep 19Sep 24Sep 27Sep 30Oct 2Oct 5Oct 7Oct 11Oct 16
28°FSep 27Oct 1Oct 5Oct 10Oct 12Oct 16Oct 19Oct 22Oct 27
24°FOct 8Oct 14Oct 18Oct 22Oct 25Oct 29Oct 31Nov 3Nov 7
20°FOct 19Oct 26Oct 31Nov 1Nov 4Nov 6Nov 9Nov 13Nov 18
16°FOct 28Nov 3Nov 6Nov 10Nov 13Nov 16Nov 19Nov 22Nov 27

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°F132124119115110105999077
32°F158152146140135129123116103
28°F183176170166161155149142130
24°F210203197192187183176171161
20°F239230225219215210203197185
16°F261255249243238233227222211

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
7,258
Cooling degree days, base 65°F
608
Growing degree days, base 40°F
4,580
Growing degree days, base 45°F
3,509
Growing degree days, base 50°F
2,582
Growing degree days, base 55°F
1,793
Growing degree days, base 60°F
1,133

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,49900
February1,11400
March81206
April536051
May28110223
June6996480
July4269730
August9197652
September13236361
October504079
November92102
December1,37600

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 0.7 km from Fort Duchesne. 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 USC00422996 (Ft Duchesne). Public domain.