McCammon climate

McCammon Frost Dates and Growing Season

NOAA 1991-2020 normals for Mccammon, 0.1 km from McCammon, elevation 4770 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mccammon. 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 24, a growing season of about 121 days.

Median at 36°F
last June 11, first September 11
Median at 32°F
last May 23, first September 24
Median at 28°F
last May 4, first October 4

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 28Jun 21Jun 17Jun 14Jun 11Jun 7Jun 4May 31May 24
32°FJun 10Jun 5May 31May 27May 23May 19May 15May 11May 6
28°FMay 21May 14May 10May 7May 4May 2Apr 29Apr 26Apr 20
24°FMay 3Apr 29Apr 26Apr 23Apr 19Apr 17Apr 13Apr 8Apr 2
20°FApr 18Apr 12Apr 7Apr 4Apr 1Mar 29Mar 25Mar 17Mar 12
16°FApr 3Mar 28Mar 21Mar 16Mar 12Mar 8Mar 5Mar 2Feb 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 4Sep 7Sep 11Sep 14Sep 17Sep 20Sep 25
32°FSep 7Sep 13Sep 18Sep 21Sep 24Sep 26Sep 29Oct 2Oct 7
28°FSep 20Sep 26Sep 30Oct 2Oct 4Oct 7Oct 11Oct 15Oct 19
24°FOct 2Oct 6Oct 11Oct 14Oct 17Oct 19Oct 23Oct 27Nov 1
20°FOct 14Oct 18Oct 22Oct 25Oct 28Oct 31Nov 3Nov 8Nov 14
16°FOct 23Oct 28Nov 1Nov 4Nov 7Nov 11Nov 16Nov 21Nov 25

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°F11210498938986817569
32°F14313713112612111811210699
28°F172165159156152147143137130
24°F202195190184180176171166160
20°F235226220215210206201195187
16°F262254248242238234229221213

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
7,219
Cooling degree days, base 65°F
348
Growing degree days, base 40°F
3,971
Growing degree days, base 45°F
2,932
Growing degree days, base 50°F
2,057
Growing degree days, base 55°F
1,334
Growing degree days, base 60°F
765

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,29000
February1,04400
March85403
April591031
May3533158
June14237351
July19163609
August31128563
September19517284
October563057
November90602
December1,23100

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 0.1 km from McCammon. 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 USC00105716 (Mccammon). Public domain.