Shoshone climate

Shoshone Frost Dates and Growing Season

NOAA 1991-2020 normals for Shoshone 1 Wnw, 0.9 km from Shoshone, elevation 3950 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Shoshone 1 Wnw. 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 24 and the first fall freeze around October 16, a growing season of about 173 days.

Median at 36°F
last May 9, first October 4
Median at 32°F
last April 24, first October 16
Median at 28°F
last April 9, first October 26

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°FMay 31May 25May 19May 14May 9May 6May 3Apr 29Apr 24
32°FMay 12May 5May 1Apr 28Apr 24Apr 21Apr 18Apr 14Apr 9
28°FApr 28Apr 22Apr 16Apr 12Apr 9Apr 6Apr 2Mar 30Mar 21
24°FApr 12Apr 4Mar 31Mar 26Mar 20Mar 15Mar 11Mar 7Mar 3
20°FMar 21Mar 13Mar 9Mar 6Mar 3Mar 1Feb 26Feb 21Feb 15
16°FMar 8Mar 3Feb 28Feb 25Feb 21Feb 17Feb 13Feb 7Jan 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 22Sep 26Sep 29Oct 1Oct 4Oct 7Oct 10Oct 13Oct 18
32°FOct 2Oct 6Oct 10Oct 13Oct 16Oct 19Oct 21Oct 25Nov 1
28°FOct 12Oct 17Oct 20Oct 23Oct 26Oct 29Nov 1Nov 4Nov 11
24°FOct 20Oct 26Oct 30Nov 2Nov 6Nov 10Nov 14Nov 19Nov 24
20°FOct 31Nov 5Nov 10Nov 14Nov 18Nov 22Nov 26Nov 29Dec 5
16°FNov 8Nov 15Nov 21Nov 25Nov 28Dec 1Dec 6Dec 11Dec 19

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°F166160154148144139134127118
32°F195188182178173168163159151
28°F226217209203198193188182174
24°F255246238233227222216209199
20°F285275269264258254248241231
16°F312303294287281276270264257

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
5,541
Cooling degree days, base 65°F
1,095
Growing degree days, base 40°F
5,631
Growing degree days, base 45°F
4,411
Growing degree days, base 50°F
3,355
Growing degree days, base 55°F
2,454
Growing degree days, base 60°F
1,708

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,07700
February85201
March664022
April4294103
May19547329
June52165563
July3403865
August7353811
September81115487
October3798158
November741017
December1,06100

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 0.9 km from Shoshone. 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 USC00108380 (Shoshone 1 Wnw). Public domain.