Vermilion climate

Vermilion Frost Dates and Growing Season

NOAA 1991-2020 normals for Oberlin, 19.9 km from Vermilion, elevation 816 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Oberlin. 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 27 and the first fall freeze around October 22, a growing season of about 178 days.

Median at 36°F
last May 7, first October 10
Median at 32°F
last April 27, first October 22
Median at 28°F
last April 15, first November 3

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

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 4Oct 7Oct 10Oct 13Oct 16Oct 19Oct 24
32°FOct 7Oct 12Oct 17Oct 19Oct 22Oct 25Oct 28Oct 31Nov 4
28°FOct 21Oct 27Oct 31Nov 1Nov 3Nov 6Nov 9Nov 12Nov 17
24°FNov 2Nov 6Nov 9Nov 11Nov 14Nov 17Nov 20Nov 25Nov 30
20°FNov 10Nov 14Nov 17Nov 21Nov 25Nov 28Dec 1Dec 5Dec 12
16°FNov 17Nov 24Nov 29Dec 1Dec 5Dec 10Dec 14Dec 19Dec 25

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°F174168163159155151146140133
32°F197191187183178174169164155
28°F223216211207203199194189181
24°F247239234229226222218213206
20°F271264257252248243239233227
16°F293284279274268264259253246

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
6,145
Cooling degree days, base 65°F
731
Growing degree days, base 40°F
5,137
Growing degree days, base 45°F
3,977
Growing degree days, base 50°F
2,959
Growing degree days, base 55°F
2,073
Growing degree days, base 60°F
1,324

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,21202
February1,03002
March868022
April5008105
May21049318
June47163566
July6243702
August13187639
September10773419
October3979151
November717031
December1,03705

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 19.9 km from Vermilion. 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 USC00336196 (Oberlin). Public domain.