Edgemont climate

Edgemont Frost Dates and Growing Season

NOAA 1991-2020 normals for Edgemont, 1.5 km from Edgemont, elevation 3432 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Edgemont. 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 23 and the first fall freeze around September 20, a growing season of about 117 days.

Median at 36°F
last June 4, first September 10
Median at 32°F
last May 23, first September 20
Median at 28°F
last May 13, first September 28

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 21Jun 15Jun 11Jun 7Jun 4Jun 1May 30May 26May 22
32°FJun 7Jun 1May 29May 26May 23May 21May 18May 15May 11
28°FMay 27May 22May 18May 16May 13May 11May 8May 6May 2
24°FMay 16May 12May 9May 6May 4May 1Apr 29Apr 25Apr 20
20°FMay 7May 2Apr 30Apr 27Apr 24Apr 21Apr 17Apr 13Apr 8
16°FApr 29Apr 24Apr 20Apr 16Apr 13Apr 8Apr 4Mar 31Mar 26

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°FAug 28Sep 1Sep 5Sep 8Sep 10Sep 13Sep 15Sep 19Sep 23
32°FSep 6Sep 11Sep 15Sep 17Sep 20Sep 23Sep 25Sep 28Oct 2
28°FSep 15Sep 19Sep 23Sep 26Sep 28Oct 1Oct 3Oct 5Oct 9
24°FSep 22Sep 27Oct 1Oct 3Oct 5Oct 8Oct 11Oct 14Oct 20
20°FSep 29Oct 4Oct 9Oct 12Oct 15Oct 18Oct 20Oct 24Oct 28
16°FOct 9Oct 14Oct 17Oct 20Oct 23Oct 25Oct 29Nov 1Nov 5

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°F1161091041019794908577
32°F13513012512111711310910498
28°F153147143139136132128124118
24°F172165161157153150146142136
20°F194188183177173169165159152
16°F214206201196191187183177170

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
7,990
Cooling degree days, base 65°F
533
Growing degree days, base 40°F
4,133
Growing degree days, base 45°F
3,151
Growing degree days, base 50°F
2,308
Growing degree days, base 55°F
1,591
Growing degree days, base 60°F
997

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,42800
February1,17300
March95608
April650039
May3729174
June10777425
July16227676
August32177612
September20541313
October635159
November1,02503
December1,39200

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 1.5 km from Edgemont. 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 USC00392557 (Edgemont). Public domain.