Spencer County climate

Spencer County Frost Dates and Growing Season

NOAA 1991-2020 normals for Taylorsville Lake, 3.9 km from Spencer County, elevation 700 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Taylorsville Lake. 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 23 and the first fall freeze around October 16, a growing season of about 176 days.

Median at 36°F
last May 2, first October 8
Median at 32°F
last April 23, first October 16
Median at 28°F
last April 10, first October 25

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 19May 13May 8May 5May 2Apr 30Apr 27Apr 23Apr 18
32°FMay 7May 2Apr 28Apr 25Apr 23Apr 19Apr 16Apr 12Apr 8
28°FApr 28Apr 21Apr 16Apr 13Apr 10Apr 7Apr 4Mar 31Mar 23
24°FApr 14Apr 7Apr 4Apr 1Mar 29Mar 24Mar 20Mar 16Mar 8
20°FApr 2Mar 28Mar 21Mar 17Mar 14Mar 10Mar 6Mar 1Feb 23
16°FMar 21Mar 15Mar 11Mar 6Mar 1Feb 27Feb 21Feb 16Feb 7

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

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°F176171166162158154150145139
32°F198190184180176172167162155
28°F221212207202198193189183175
24°F250242235229224218213208199
20°F278269263256251246240232223
16°F305295289282277272265259250

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
4,594
Cooling degree days, base 65°F
1,321
Growing degree days, base 40°F
6,599
Growing degree days, base 45°F
5,251
Growing degree days, base 50°F
4,053
Growing degree days, base 55°F
3,005
Growing degree days, base 60°F
2,096

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,00108
February794018
March608379
April30618217
May102112478
June6259703
July0377841
August1336800
September45182587
October28431249
November580359
December866013

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 3.9 km from Spencer 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 USC00157950 (Taylorsville Lake). Public domain.