Bellefontaine climate

Bellefontaine Frost Dates and Growing Season

NOAA 1991-2020 normals for Coden, 16.7 km from Bellefontaine, elevation 12 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Coden. 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 March 13 and the first fall freeze around November 24, a growing season of about 255 days.

Median at 36°F
last March 26, first November 11
Median at 32°F
last March 13, first November 24
Median at 28°F
last February 27, first December 8

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°FApr 12Apr 6Apr 2Mar 30Mar 26Mar 21Mar 17Mar 12Mar 4
32°FApr 2Mar 26Mar 21Mar 17Mar 13Mar 8Mar 3Feb 27Feb 18
28°FMar 19Mar 12Mar 7Mar 2Feb 27Feb 21Feb 15Feb 3Jan 24
24°FMar 6Feb 28Feb 20Feb 12Feb 4Jan 31Jan 22Jan 13Jan 1
20°FFeb 26Feb 11Feb 3Jan 31Jan 23Jan 17Jan 9Jan 2Dec 25
16°FFeb 8Feb 3Jan 31Jan 24Jan 17Jan 10Jan 6Jan 2Dec 28

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°FOct 28Nov 1Nov 4Nov 8Nov 11Nov 15Nov 19Nov 24Dec 1
32°FNov 4Nov 11Nov 15Nov 20Nov 24Nov 28Dec 3Dec 7Dec 22
28°FNov 15Nov 22Nov 29Dec 4Dec 8Dec 15Dec 25Jan 3Jan 14
24°FDec 1Dec 8Dec 16Dec 25Jan 1Jan 5Jan 11Jan 19Feb 4
20°FDec 11Dec 23Dec 31Jan 2Jan 6Jan 14Jan 20Feb 1Feb 10
16°FDec 26Jan 1Jan 2Jan 6Jan 9Jan 17Jan 27Feb 1Feb 5

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°F258250243237232227222216209
32°F286276267261255250244238230
28°F331315306298290282274265254
24°F365354342334329319309303290
20°F365365365365362352343334319
16°F365365365365365365365365352

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
99% of years
24°F or colder
87% of years
20°F or colder
51% of years
16°F or colder
18% 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
1,834
Cooling degree days, base 65°F
2,261
Growing degree days, base 40°F
9,593
Growing degree days, base 45°F
7,854
Growing degree days, base 50°F
6,220
Growing degree days, base 55°F
4,730
Growing degree days, base 60°F
3,405

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January4754116
February3437143
March22325286
April7687462
May9240696
June0393843
July0477942
August0476941
September1362811
October57153562
November23828265
December41310152

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 16.7 km from Bellefontaine. 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 USC00011803 (Coden). Public domain.