Metcalfe County climate

Metcalfe County Frost Dates and Growing Season

NOAA 1991-2020 normals for Knob Lick 4S, 7.2 km from Metcalfe County, elevation 1020 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Knob Lick 4S. 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 5 and the first fall freeze around November 2, a growing season of about 211 days.

Median at 36°F
last April 18, first October 24
Median at 32°F
last April 5, first November 2
Median at 28°F
last March 25, first November 14

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 8May 2Apr 26Apr 22Apr 18Apr 15Apr 12Apr 8Apr 3
32°FApr 24Apr 16Apr 11Apr 8Apr 5Apr 2Mar 30Mar 27Mar 21
28°FApr 8Apr 3Mar 31Mar 28Mar 25Mar 22Mar 19Mar 15Mar 9
24°FMar 30Mar 25Mar 21Mar 18Mar 15Mar 12Mar 7Mar 2Feb 24
20°FMar 21Mar 16Mar 12Mar 6Mar 3Feb 28Feb 23Feb 16Feb 7
16°FMar 14Mar 5Mar 1Feb 25Feb 20Feb 11Feb 6Feb 1Jan 24

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 12Oct 17Oct 20Oct 22Oct 24Oct 26Oct 29Oct 31Nov 4
32°FOct 21Oct 25Oct 29Oct 31Nov 2Nov 5Nov 8Nov 11Nov 18
28°FNov 1Nov 4Nov 8Nov 11Nov 14Nov 17Nov 22Nov 27Dec 2
24°FNov 8Nov 14Nov 18Nov 22Nov 26Nov 30Dec 3Dec 7Dec 15
20°FNov 17Nov 25Nov 30Dec 2Dec 7Dec 12Dec 18Dec 23Dec 28
16°FNov 30Dec 6Dec 12Dec 19Dec 23Dec 26Dec 30Jan 4Jan 13

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°F206199195191186182177171165
32°F231223218214211207203197187
28°F254247241236233228224219212
24°F281272265259254250245240232
20°F310299291285280274267261253
16°F334325317308302296289282272

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
4,263
Cooling degree days, base 65°F
1,343
Growing degree days, base 40°F
6,855
Growing degree days, base 45°F
5,452
Growing degree days, base 50°F
4,197
Growing degree days, base 55°F
3,099
Growing degree days, base 60°F
2,152

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January948014
February753022
March581488
April27025249
May90114491
June4264709
July0368832
August1343807
September39187599
October23835286
November537477
December801024

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 7.2 km from Metcalfe 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 USC00154449 (Knob Lick 4S). Public domain.