Morris County climate

Morris County Frost Dates and Growing Season

NOAA 1991-2020 normals for Council Grove Lake, 12.2 km from Morris County, elevation 1315 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Council Grove 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 11 and the first fall freeze around October 25, a growing season of about 194 days.

Median at 36°F
last April 21, first October 15
Median at 32°F
last April 11, 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 5May 1Apr 28Apr 25Apr 21Apr 18Apr 15Apr 12Apr 6
32°FApr 27Apr 21Apr 18Apr 14Apr 11Apr 8Apr 5Apr 1Mar 27
28°FApr 17Apr 11Apr 7Apr 4Apr 1Mar 30Mar 26Mar 21Mar 14
24°FApr 6Apr 1Mar 29Mar 26Mar 21Mar 17Mar 13Mar 9Mar 3
20°FMar 29Mar 23Mar 18Mar 14Mar 10Mar 7Mar 4Feb 28Feb 24
16°FMar 18Mar 13Mar 8Mar 5Mar 2Feb 28Feb 25Feb 19Feb 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 30Oct 5Oct 10Oct 13Oct 15Oct 18Oct 20Oct 23Oct 27
32°FOct 11Oct 16Oct 19Oct 22Oct 25Oct 27Oct 30Nov 2Nov 6
28°FOct 20Oct 25Oct 28Nov 1Nov 2Nov 5Nov 8Nov 12Nov 17
24°FOct 28Nov 1Nov 4Nov 7Nov 11Nov 14Nov 18Nov 22Nov 27
20°FNov 3Nov 9Nov 13Nov 17Nov 21Nov 24Nov 28Dec 1Dec 9
16°FNov 12Nov 20Nov 25Nov 29Dec 2Dec 6Dec 10Dec 15Dec 23

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°F194188182178174170166161155
32°F215207203198194190186180173
28°F236227222217213209205200191
24°F259251246241236231225219212
20°F281272266261255251245240231
16°F302293286280275271266258249

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
4,948
Cooling degree days, base 65°F
1,523
Growing degree days, base 40°F
6,686
Growing degree days, base 45°F
5,384
Growing degree days, base 50°F
4,221
Growing degree days, base 55°F
3,191
Growing degree days, base 60°F
2,290

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,08602
February861011
March633473
April32222212
May105109473
June8302744
July0457922
August1404868
September52188588
October28034264
November626258
December97305

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 12.2 km from Morris 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 USC00141867 (Council Grove Lake). Public domain.