Logan climate

Logan Frost Dates and Growing Season

NOAA 1991-2020 normals for Logan Radio Kvnu, 1.9 km from Logan, elevation 4475 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Logan Radio Kvnu. 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 8 and the first fall freeze around October 2, a growing season of about 145 days.

Median at 36°F
last May 27, first September 21
Median at 32°F
last May 8, first October 2
Median at 28°F
last April 23, first October 14

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 13Jun 8Jun 4May 31May 27May 22May 18May 15May 10
32°FJun 2May 21May 16May 12May 8May 6May 3Apr 30Apr 25
28°FMay 7May 2Apr 29Apr 26Apr 23Apr 20Apr 16Apr 12Apr 6
24°FApr 23Apr 18Apr 14Apr 9Apr 6Apr 2Mar 29Mar 23Mar 16
20°FApr 6Mar 31Mar 27Mar 22Mar 17Mar 14Mar 11Mar 8Mar 4
16°FMar 23Mar 16Mar 11Mar 9Mar 6Mar 4Mar 2Feb 27Feb 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°FSep 6Sep 11Sep 15Sep 18Sep 21Sep 23Sep 27Oct 1Oct 5
32°FSep 18Sep 22Sep 26Sep 30Oct 2Oct 5Oct 7Oct 11Oct 15
28°FSep 29Oct 3Oct 7Oct 11Oct 14Oct 16Oct 19Oct 22Oct 26
24°FOct 13Oct 17Oct 21Oct 23Oct 26Oct 28Nov 1Nov 4Nov 9
20°FOct 22Oct 27Oct 31Nov 3Nov 6Nov 10Nov 14Nov 18Nov 23
16°FNov 1Nov 6Nov 11Nov 15Nov 18Nov 21Nov 25Nov 28Dec 2

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°F1371301241191141101049890
32°F164157152148145140135130121
28°F194187181177173169164159151
24°F226219212207203198193188180
20°F255247241236231227221215208
16°F276269264259255251246239232

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
7,007
Cooling degree days, base 65°F
519
Growing degree days, base 40°F
4,367
Growing degree days, base 45°F
3,295
Growing degree days, base 50°F
2,381
Growing degree days, base 55°F
1,622
Growing degree days, base 60°F
1,002

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,30500
February1,06000
March82506
April561044
May3168193
June10866412
July11230683
August17182631
September15933335
October524172
November87303
December1,24800

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 1.9 km from Logan. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00425182 (Logan Radio Kvnu). Public domain.