McCall climate

McCall Frost Dates and Growing Season

NOAA 1991-2020 normals for Mccall, 2.7 km from McCall, elevation 5025 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mccall. 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 June 22 and the first fall freeze around September 2, a growing season of about 72 days.

Median at 32°F
last June 22, first September 2
Median at 28°F
last June 3, first September 15

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 10Jul 3Jun 29Jun 26Jun 22Jun 19Jun 15Jun 11Jun 3
28°FJun 23Jun 18Jun 12Jun 7Jun 3May 30May 24May 18May 12
24°FJun 1May 22May 15May 11May 7May 4Apr 30Apr 27Apr 21
20°FMay 6Apr 30Apr 27Apr 23Apr 19Apr 16Apr 12Apr 8Apr 3
16°FApr 21Apr 15Apr 11Apr 8Apr 6Apr 3Mar 31Mar 27Mar 20

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°FAug 14Aug 23Aug 28Aug 31Sep 2Sep 5Sep 8Sep 12Sep 18
28°FAug 30Sep 3Sep 7Sep 11Sep 15Sep 19Sep 22Sep 27Oct 2
24°FSep 9Sep 17Sep 21Sep 26Sep 29Oct 2Oct 5Oct 8Oct 13
20°FSep 26Oct 1Oct 5Oct 8Oct 12Oct 15Oct 19Oct 24Oct 30
16°FOct 6Oct 14Oct 18Oct 22Oct 26Oct 30Nov 1Nov 6Nov 13

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°F676055504439343024
32°F968982777266615546
28°F13212311610910396918475
24°F169160154149144138133124115
20°F200192186180176170165158151
16°F227218212208203198193187179

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
8,734
Cooling degree days, base 65°F
95
Growing degree days, base 40°F
2,768
Growing degree days, base 45°F
1,920
Growing degree days, base 50°F
1,226
Growing degree days, base 55°F
686
Growing degree days, base 60°F
307

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,33300
February1,11400
March1,03500
April78406
May523067
June3126176
July10549411
August11836386
September3414158
October698021
November1,03400
December1,33700

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 2.7 km from McCall. 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 USC00105708 (Mccall). Public domain.