Chillicothe climate

Chillicothe Frost Dates and Growing Season

NOAA 1991-2020 normals for Lacon, 12.3 km from Chillicothe, elevation 458 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lacon. 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 20 and the first fall freeze around October 17, a growing season of about 178 days.

Median at 36°F
last May 2, first October 7
Median at 32°F
last April 20, first October 17
Median at 28°F
last April 7, first October 28

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

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°F177170165161157153148143135
32°F200193187182178174169164156
28°F224216210206203199194189180
24°F249240234229224219214209203
20°F271264257252247242236230222
16°F290280274269264259255248240

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
5,603
Cooling degree days, base 65°F
1,134
Growing degree days, base 40°F
5,952
Growing degree days, base 45°F
4,740
Growing degree days, base 50°F
3,652
Growing degree days, base 55°F
2,685
Growing degree days, base 60°F
1,841

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,21201
February98303
March734143
April37615164
May13179418
June13247684
July0343808
August4292753
September65135522
October33122213
November693040
December1,06204

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 12.3 km from Chillicothe. 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 USC00114805 (Lacon). Public domain.