Enterprise climate

Enterprise Frost Dates and Growing Season

NOAA 1991-2020 normals for Joseph, 9.5 km from Enterprise, elevation 4184 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Joseph. 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 24 and the first fall freeze around October 1, a growing season of about 126 days.

Median at 32°F
last May 24, first October 1
Median at 28°F
last May 4, first October 13

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°FJul 6Jun 18Jun 7May 31May 24May 19May 15May 11May 6
28°FMay 26May 16May 11May 7May 4May 1Apr 29Apr 26Apr 21
24°FMay 5May 1Apr 28Apr 24Apr 21Apr 17Apr 13Apr 9Apr 4
20°FApr 22Apr 15Apr 10Apr 6Apr 2Mar 30Mar 24Mar 18Mar 11
16°FApr 4Mar 28Mar 22Mar 17Mar 12Mar 8Mar 4Feb 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°F–––––––––
32°FSep 10Sep 19Sep 24Sep 27Oct 1Oct 3Oct 6Oct 10Oct 15
28°FSep 29Oct 3Oct 6Oct 10Oct 13Oct 16Oct 20Oct 24Oct 30
24°FOct 9Oct 15Oct 18Oct 22Oct 25Oct 28Nov 1Nov 4Nov 9
20°FOct 18Oct 25Oct 29Nov 1Nov 4Nov 7Nov 11Nov 15Nov 19
16°FOct 29Nov 3Nov 8Nov 12Nov 15Nov 18Nov 22Nov 24Nov 29

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°F119109102948680726452
32°F1521451391321261191109782
28°F182175169164160155151145133
24°F210202196190186181176171165
20°F242234227221216211206199190
16°F270262256251246240235228217

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
7,749
Cooling degree days, base 65°F
184
Growing degree days, base 40°F
3,209
Growing degree days, base 45°F
2,277
Growing degree days, base 50°F
1,511
Growing degree days, base 55°F
904
Growing degree days, base 60°F
465

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,18300
February1,00200
March89202
April717016
May476399
June27111211
July10272439
August9075453
September26221242
October620046
November93303
December1,20200

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 9.5 km from Enterprise. 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 USC00354329 (Joseph). Public domain.