Eagle climate

Eagle Frost Dates and Growing Season

NOAA 1991-2020 normals for Shoshone, 35.3 km from Eagle, elevation 5992 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Shoshone. 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 1 and the first fall freeze around October 14, a growing season of about 164 days.

Median at 36°F
last May 14, first October 6
Median at 32°F
last May 1, first October 14
Median at 28°F
last April 21, first October 23

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 1May 25May 21May 17May 14May 10May 7May 4May 1
32°FMay 14May 9May 6May 4May 1Apr 30Apr 28Apr 24Apr 19
28°FMay 4Apr 30Apr 27Apr 24Apr 21Apr 18Apr 15Apr 12Apr 6
24°FApr 24Apr 19Apr 15Apr 11Apr 8Apr 5Apr 1Mar 29Mar 20
20°FApr 12Apr 6Apr 2Mar 30Mar 26Mar 22Mar 17Mar 13Mar 8
16°FApr 2Mar 27Mar 21Mar 17Mar 13Mar 9Mar 6Mar 2Feb 24

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 25Sep 29Oct 1Oct 4Oct 6Oct 8Oct 11Oct 13Oct 17
32°FOct 1Oct 6Oct 8Oct 11Oct 14Oct 16Oct 19Oct 22Oct 27
28°FOct 11Oct 15Oct 18Oct 20Oct 23Oct 25Oct 29Nov 1Nov 6
24°FOct 19Oct 23Oct 26Oct 29Nov 1Nov 4Nov 7Nov 11Nov 16
20°FOct 26Oct 30Nov 3Nov 6Nov 10Nov 13Nov 17Nov 20Nov 24
16°FNov 3Nov 8Nov 13Nov 16Nov 19Nov 22Nov 24Nov 28Dec 3

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°F161155150146143139136130123
32°F181175171168164160156152146
28°F204198193188184180177172166
24°F227220215210206202198193186
20°F249242236231227222217212205
16°F270265259254249244238231222

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
6,260
Cooling degree days, base 65°F
721
Growing degree days, base 40°F
4,983
Growing degree days, base 45°F
3,840
Growing degree days, base 50°F
2,846
Growing degree days, base 55°F
2,004
Growing degree days, base 60°F
1,304

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,23500
February93900
March75207
April501052
May24713252
June55121517
July1287751
August2225688
September8274446
October4181127
November81207
December1,21600

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 35.3 km from Eagle. 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 USC00057618 (Shoshone). Public domain.