Clinton County climate

Clinton County Frost Dates and Growing Season

NOAA 1991-2020 normals for Byrdstown, 16.5 km from Clinton County, elevation 880 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Byrdstown. 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 12 and the first fall freeze around October 25, a growing season of about 196 days.

Median at 36°F
last April 26, first October 16
Median at 32°F
last April 12, first October 25
Median at 28°F
last March 31, 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 11May 6May 2Apr 29Apr 26Apr 22Apr 19Apr 16Apr 11
32°FApr 30Apr 24Apr 20Apr 16Apr 12Apr 8Apr 5Apr 2Mar 28
28°FApr 16Apr 10Apr 5Apr 2Mar 31Mar 28Mar 24Mar 19Mar 14
24°FApr 4Mar 31Mar 27Mar 21Mar 18Mar 14Mar 9Mar 3Feb 26
20°FMar 23Mar 17Mar 12Mar 6Mar 2Feb 27Feb 23Feb 17Feb 8
16°FMar 13Mar 4Feb 28Feb 25Feb 20Feb 13Feb 7Feb 1Jan 23

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 3Oct 7Oct 10Oct 13Oct 16Oct 18Oct 21Oct 25Oct 29
32°FOct 13Oct 17Oct 20Oct 23Oct 25Oct 28Oct 30Nov 2Nov 6
28°FOct 22Oct 26Oct 30Nov 1Nov 3Nov 6Nov 10Nov 14Nov 20
24°FNov 2Nov 7Nov 10Nov 14Nov 17Nov 20Nov 24Nov 30Dec 5
20°FNov 11Nov 17Nov 22Nov 27Dec 1Dec 4Dec 9Dec 17Dec 25
16°FNov 24Dec 2Dec 7Dec 14Dec 20Dec 24Dec 30Jan 3Jan 14

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°F194186181177173169164159152
32°F216208204199196191186181173
28°F242233227222218214209205198
24°F271262255249243237232226219
20°F301293285277270264260252241
16°F330322313307302296290281267

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
99% 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
4,125
Cooling degree days, base 65°F
1,150
Growing degree days, base 40°F
6,710
Growing degree days, base 45°F
5,291
Growing degree days, base 50°F
4,023
Growing degree days, base 55°F
2,911
Growing degree days, base 60°F
1,953

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January893021
February709129
March542597
April26926250
May9593467
June8228670
July1328792
August2293756
September43148556
October24928273
November532178
December783033

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 16.5 km from Clinton 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 USC00401310 (Byrdstown). Public domain.