Logan climate

Logan Frost Dates and Growing Season

NOAA 1991-2020 normals for Mccarty Rch, 26.7 km from Logan, elevation 4410 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mccarty Rch. 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 20 and the first fall freeze around October 21, a growing season of about 183 days.

Median at 36°F
last May 1, first October 13
Median at 32°F
last April 20, first October 21
Median at 28°F
last April 8, first November 1

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 13May 9May 5May 3May 1Apr 28Apr 25Apr 22Apr 17
32°FMay 5Apr 30Apr 26Apr 23Apr 20Apr 18Apr 14Apr 11Apr 6
28°FApr 26Apr 20Apr 16Apr 12Apr 8Apr 6Apr 3Mar 30Mar 25
24°FApr 14Apr 7Apr 3Mar 31Mar 28Mar 24Mar 19Mar 15Mar 8
20°FApr 2Mar 27Mar 22Mar 17Mar 14Mar 9Mar 5Mar 1Feb 23
16°FMar 21Mar 14Mar 8Mar 4Mar 1Feb 25Feb 20Feb 15Feb 5

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 30Oct 4Oct 7Oct 10Oct 13Oct 16Oct 18Oct 20Oct 23
32°FOct 6Oct 13Oct 16Oct 19Oct 21Oct 23Oct 26Oct 29Nov 3
28°FOct 18Oct 22Oct 26Oct 29Nov 1Nov 3Nov 5Nov 8Nov 13
24°FOct 25Oct 31Nov 3Nov 5Nov 9Nov 12Nov 15Nov 18Nov 22
20°FNov 2Nov 6Nov 11Nov 14Nov 18Nov 21Nov 24Nov 27Dec 3
16°FNov 11Nov 17Nov 21Nov 24Nov 27Dec 1Dec 5Dec 11Dec 18

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°F181175170167164160156152146
32°F202195191187183179174170163
28°F224217212208203198194189183
24°F250241235230226222217212205
20°F273265259253248242237231222
16°F304291284278273267261254244

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
4,282
Cooling degree days, base 65°F
1,204
Growing degree days, base 40°F
6,589
Growing degree days, base 45°F
5,179
Growing degree days, base 50°F
3,937
Growing degree days, base 55°F
2,865
Growing degree days, base 60°F
1,955

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January87104
February696016
March540179
April3069201
May10277444
June7259702
July0377842
August1321784
September44145554
October26716248
November579058
December86907

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 26.7 km from Logan. 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 USC00295516 (Mccarty Rch). Public domain.