Traverse County climate

Traverse County Frost Dates and Growing Season

NOAA 1991-2020 normals for Wheaton, 4.7 km from Traverse County, elevation 1018 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Wheaton. 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 1 and the first fall freeze around October 9, a growing season of about 160 days.

Median at 36°F
last May 9, first September 30
Median at 32°F
last May 1, first October 9
Median at 28°F
last April 21, first October 20

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 21May 17May 14May 11May 9May 6May 4May 1Apr 28
32°FMay 12May 8May 5May 2May 1Apr 29Apr 26Apr 23Apr 18
28°FMay 3Apr 30Apr 27Apr 24Apr 21Apr 19Apr 16Apr 12Apr 8
24°FApr 25Apr 21Apr 18Apr 15Apr 12Apr 9Apr 7Apr 4Mar 31
20°FApr 19Apr 13Apr 10Apr 7Apr 5Apr 2Mar 31Mar 27Mar 20
16°FApr 11Apr 7Apr 3Apr 1Mar 30Mar 25Mar 22Mar 18Mar 13

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

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°F160155151147144141137133127
32°F179173168164160157154150145
28°F199193188183179176172168161
24°F218211205202199194191185179
20°F234226222218214210206201194
16°F248241236233228224220216209

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
8,323
Cooling degree days, base 65°F
666
Growing degree days, base 40°F
4,531
Growing degree days, base 45°F
3,536
Growing degree days, base 50°F
2,648
Growing degree days, base 55°F
1,867
Growing degree days, base 60°F
1,204

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,66100
February1,38700
March1,11804
April636150
May26236275
June43145552
July9238694
August22182625
September16359356
October557586
November1,00106
December1,46500

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 4.7 km from Traverse County. 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 USC00218907 (Wheaton). Public domain.