Scioto County climate

Scioto County Frost Dates and Growing Season

NOAA 1991-2020 normals for Portsmouth-Sciotoville, 10.6 km from Scioto County, elevation 540 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Portsmouth-Sciotoville. 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 17 and the first fall freeze around October 25, a growing season of about 191 days.

Median at 36°F
last April 30, first October 15
Median at 32°F
last April 17, first October 25
Median at 28°F
last April 4, first November 4

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 15May 10May 6May 2Apr 30Apr 26Apr 23Apr 19Apr 13
32°FMay 5Apr 28Apr 24Apr 20Apr 17Apr 14Apr 10Apr 7Apr 3
28°FApr 20Apr 15Apr 10Apr 6Apr 4Apr 1Mar 29Mar 25Mar 19
24°FApr 6Apr 1Mar 30Mar 26Mar 23Mar 19Mar 16Mar 11Mar 4
20°FMar 27Mar 21Mar 17Mar 14Mar 10Mar 6Mar 2Feb 26Feb 18
16°FMar 17Mar 11Mar 6Mar 3Feb 28Feb 23Feb 17Feb 10Feb 3

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

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°F188181176172168164159154148
32°F210203199194191186182175167
28°F234228223219214211206201194
24°F261253247241237233229223216
20°F292282274268263258252246239
16°F319309302297290285278270262

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
4,788
Cooling degree days, base 65°F
1,142
Growing degree days, base 40°F
6,264
Growing degree days, base 45°F
4,949
Growing degree days, base 50°F
3,784
Growing degree days, base 55°F
2,763
Growing degree days, base 60°F
1,883

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,02006
February83707
March659155
April32213199
May11486441
June11232670
July0343808
August2302766
September47143546
October29220228
November605049
December879010

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 10.6 km from Scioto 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 USC00336781 (Portsmouth-Sciotoville). Public domain.