Mountain Green climate

Mountain Green Frost Dates and Growing Season

NOAA 1991-2020 normals for Weber Basin Pump Plt 3, 10.8 km from Mountain Green, elevation 4900 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Weber Basin Pump Plt 3. 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 April 29 and the first fall freeze around October 20, a growing season of about 172 days.

Median at 36°F
last May 15, first October 7
Median at 32°F
last April 29, first October 20
Median at 28°F
last April 13, first November 2

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 10Jun 4May 30May 22May 15May 10May 5Apr 30Apr 26
32°FMay 25May 13May 6May 2Apr 29Apr 25Apr 20Apr 15Apr 6
28°FMay 5Apr 28Apr 23Apr 18Apr 13Apr 8Apr 2Mar 28Mar 16
24°FApr 21Apr 13Apr 6Mar 31Mar 26Mar 18Mar 11Mar 6Feb 28
20°FApr 2Mar 24Mar 14Mar 8Mar 4Feb 28Feb 25Feb 21Feb 14
16°FMar 11Mar 2Feb 26Feb 22Feb 18Feb 14Feb 9Feb 5Jan 30

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 24Sep 28Oct 1Oct 4Oct 7Oct 11Oct 15Oct 19Oct 23
32°FOct 1Oct 7Oct 12Oct 16Oct 20Oct 24Oct 27Oct 31Nov 5
28°FOct 18Oct 23Oct 28Oct 31Nov 2Nov 5Nov 8Nov 11Nov 15
24°FOct 28Nov 2Nov 5Nov 9Nov 12Nov 15Nov 18Nov 21Nov 25
20°FNov 6Nov 11Nov 15Nov 18Nov 21Nov 23Nov 26Nov 28Dec 4
16°FNov 13Nov 19Nov 22Nov 26Nov 28Dec 1Dec 4Dec 8Dec 15

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°F169160153147141135128122114
32°F200190184178172166159151140
28°F229221214208203197190183172
24°F260250242236229224217209199
20°F283275269265259254247239228
16°F309299294288283277273266255

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
6,124
Cooling degree days, base 65°F
927
Growing degree days, base 40°F
5,130
Growing degree days, base 45°F
3,995
Growing degree days, base 50°F
3,017
Growing degree days, base 55°F
2,187
Growing degree days, base 60°F
1,493

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,14200
February89400
March727014
April537260
May25724257
June85119488
July2397861
August6295755
September10085441
October4356131
November792010
December1,14800

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 10.8 km from Mountain Green. 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 USC00429346 (Weber Basin Pump Plt 3). Public domain.