Miami County climate

Miami County Frost Dates and Growing Season

NOAA 1991-2020 normals for Wabash, 18.6 km from Miami County, elevation 665 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Wabash. 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 23 and the first fall freeze around October 21, a growing season of about 181 days.

Median at 36°F
last May 4, first October 11
Median at 32°F
last April 23, first October 21
Median at 28°F
last April 12, 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 20May 15May 11May 7May 4May 1Apr 29Apr 25Apr 20
32°FMay 9May 4Apr 30Apr 27Apr 23Apr 20Apr 17Apr 13Apr 8
28°FApr 29Apr 22Apr 18Apr 15Apr 12Apr 8Apr 5Apr 1Mar 27
24°FApr 16Apr 10Apr 6Apr 3Mar 31Mar 29Mar 25Mar 21Mar 15
20°FApr 6Apr 1Mar 29Mar 25Mar 21Mar 18Mar 14Mar 10Mar 4
16°FMar 29Mar 22Mar 17Mar 14Mar 11Mar 7Mar 4Feb 28Feb 21

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

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°F180173167163160156151146140
32°F201195189185181177172167159
28°F224217211207203199195190181
24°F250242236231227223218213205
20°F271264259253248244239233225
16°F294286279273268264257251242

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
5,841
Cooling degree days, base 65°F
938
Growing degree days, base 40°F
5,588
Growing degree days, base 45°F
4,396
Growing degree days, base 50°F
3,337
Growing degree days, base 55°F
2,404
Growing degree days, base 60°F
1,604

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,21302
February1,00403
March805028
April4369130
May16471381
June25206631
July3288750
August7234693
September82112482
October34917194
November698138
December1,05505

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 18.6 km from Miami County. 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 USC00129138 (Wabash). Public domain.