Sullivan County climate

Sullivan County Frost Dates and Growing Season

NOAA 1991-2020 normals for Liberty 1 Ne, 9.8 km from Sullivan County, elevation 1580 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Liberty 1 Ne. 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 May 9 and the first fall freeze around October 5, a growing season of about 149 days.

Median at 36°F
last May 20, first September 27
Median at 32°F
last May 9, first October 5
Median at 28°F
last April 27, first October 20

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°FJun 2May 29May 26May 23May 20May 17May 14May 11May 6
32°FMay 23May 18May 14May 12May 9May 6May 3Apr 30Apr 24
28°FMay 12May 7May 3Apr 30Apr 27Apr 23Apr 20Apr 17Apr 11
24°FApr 29Apr 22Apr 18Apr 15Apr 12Apr 10Apr 7Apr 4Apr 1
20°FApr 15Apr 10Apr 6Apr 4Apr 3Apr 1Mar 30Mar 25Mar 19
16°FApr 7Apr 3Apr 1Mar 29Mar 26Mar 23Mar 20Mar 16Mar 10

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

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°F146140136132129125122117111
32°F171165160155149145142137131
28°F198190184180175170166160153
24°F223216211207203199194188180
20°F246239233229225221217212207
16°F265258252248244240236230223

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
7,444
Cooling degree days, base 65°F
292
Growing degree days, base 40°F
3,942
Growing degree days, base 45°F
2,918
Growing degree days, base 50°F
2,033
Growing degree days, base 55°F
1,292
Growing degree days, base 60°F
706

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,33900
February1,15600
March1,04205
April648241
May34611174
June11451389
July27120558
August5081496
September20026287
October533174
November82709
December1,16201

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 9.8 km from Sullivan 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 USC00304731 (Liberty 1 Ne). Public domain.