Allen County climate

Allen County Frost Dates and Growing Season

NOAA 1991-2020 normals for Scottsville, 3.2 km from Allen County, elevation 743 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Scottsville. 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 15 and the first fall freeze around October 25, a growing season of about 194 days.

Median at 36°F
last April 27, first October 16
Median at 32°F
last April 15, first October 25
Median at 28°F
last April 1, first November 2

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

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

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°F192185180176172168165160153
32°F215207202198194189185180172
28°F239230225220215212208203195
24°F267257249244239233228221213
20°F290280273267261256250244235
16°F316305298293285278273265256

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
4,134
Cooling degree days, base 65°F
1,235
Growing degree days, base 40°F
6,828
Growing degree days, base 45°F
5,412
Growing degree days, base 50°F
4,143
Growing degree days, base 55°F
3,024
Growing degree days, base 60°F
2,053

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January918017
February713030
March5376105
April25729261
May86103484
June8237679
July1348812
August2316780
September38161573
October23732287
November532389
December806027

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 3.2 km from Allen County. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00157215 (Scottsville). Public domain.