Alanson climate

Alanson Frost Dates and Growing Season

NOAA 1991-2020 normals for Petoskey Ncmc, 15.8 km from Alanson, elevation 748 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Petoskey Ncmc. 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 16 and the first fall freeze around October 9, a growing season of about 147 days.

Median at 36°F
last May 28, first September 28
Median at 32°F
last May 16, first October 9
Median at 28°F
last May 2, first October 23

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

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

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°F141135130125122118113108101
32°F168160155151147143138133126
28°F193187182178174169164159151
24°F220212207202197192187182175
20°F245236231227223219213209201
16°F263256251246241236233227221

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
8,075
Cooling degree days, base 65°F
296
Growing degree days, base 40°F
3,721
Growing degree days, base 45°F
2,766
Growing degree days, base 50°F
1,941
Growing degree days, base 55°F
1,237
Growing degree days, base 60°F
680

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,42300
February1,27100
March1,16308
April756027
May40713156
June13753372
July54106518
August6184488
September20638294
October546271
November86309
December1,19000

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 15.8 km from Alanson. 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 USC00206510 (Petoskey Ncmc). Public domain.