El Jebel climate

El Jebel Frost Dates and Growing Season

NOAA 1991-2020 normals for Glenwood Spgs #2, 23.8 km from El Jebel, elevation 5895 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Glenwood Spgs #2. 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 13 and the first fall freeze around October 3, a growing season of about 142 days.

Median at 36°F
last May 30, first September 23
Median at 32°F
last May 13, first October 3
Median at 28°F
last April 27, first October 14

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 13Jun 7Jun 4Jun 2May 30May 26May 24May 21May 16
32°FMay 30May 24May 20May 16May 13May 10May 7May 3Apr 30
28°FMay 11May 5May 2Apr 30Apr 27Apr 25Apr 22Apr 19Apr 14
24°FApr 26Apr 23Apr 19Apr 16Apr 13Apr 10Apr 6Apr 3Mar 30
20°FApr 15Apr 7Apr 3Mar 31Mar 28Mar 24Mar 18Mar 14Mar 8
16°FApr 1Mar 24Mar 19Mar 14Mar 10Mar 6Mar 3Feb 28Feb 22

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

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°F13312712211911511210810397
32°F159153149145142138133128120
28°F185179175171167163159155148
24°F213206201197193189185180174
20°F242235230224220215211206199
16°F266258253248244239235229220

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
6,723
Cooling degree days, base 65°F
423
Growing degree days, base 40°F
4,344
Growing degree days, base 45°F
3,253
Growing degree days, base 50°F
2,323
Growing degree days, base 55°F
1,543
Growing degree days, base 60°F
905

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,26300
February97200
March78904
April570036
May3115194
June8161432
July7193651
August16141591
September14222337
October495077
November86003
December1,21700

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 23.8 km from El Jebel. 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 USC00053359 (Glenwood Spgs #2). Public domain.