Lake County climate

Lake County Frost Dates and Growing Season

NOAA 1991-2020 normals for Lisbon, 14.2 km from Lake County, elevation 68 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Lisbon. 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 February 2 and the first fall freeze around January 3, a growing season of about 327 days.

Median at 36°F
last February 20, first December 15
Median at 32°F
last February 2, first January 3
Median at 28°F
last January 21, first January 11

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°FMar 18Mar 10Mar 4Feb 27Feb 20Feb 14Feb 6Jan 31Jan 22
32°FMar 5Feb 23Feb 15Feb 7Feb 2Jan 29Jan 22Jan 14Jan 5
28°FFeb 16Feb 5Jan 31Jan 28Jan 21Jan 16Jan 12Jan 6Dec 30
24°FFeb 10Feb 1Jan 30Jan 25Jan 19Jan 13Jan 8Jan 4Dec 29
20°F–––––––––
16°F–––––––––

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°FNov 19Nov 28Dec 3Dec 8Dec 15Dec 22Dec 30Jan 6Jan 16
32°FDec 2Dec 11Dec 21Dec 29Jan 3Jan 9Jan 16Jan 24Feb 3
28°FDec 13Dec 27Jan 1Jan 6Jan 11Jan 17Jan 22Jan 29Feb 3
24°FDec 28Jan 3Jan 7Jan 12Jan 17Jan 22Jan 28Jan 31Feb 9
20°F–––––––––
16°F–––––––––

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°F332321310303297290282274264
32°F365351340333327321313304292
28°F365365365365361352341332320
24°F365365365365365365365365355
20°F365365365365365365365365365
16°F365365365365365365365365365

How often it gets that cold

The share of years with at least one night at or below each temperature.

36°F or colder
99% of years
32°F or colder
87% of years
28°F or colder
51% of years
24°F or colder
16% of years
20°F or colder
0% of years
16°F or colder
0% 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
923
Cooling degree days, base 65°F
2,821
Growing degree days, base 40°F
11,029
Growing degree days, base 45°F
9,223
Growing degree days, base 50°F
7,456
Growing degree days, base 55°F
5,772
Growing degree days, base 60°F
4,210

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January28520239
February18230284
March10375441
April24162588
May2326789
June0438888
July0499964
August0501966
September0419868
October15247698
November9873428
December21633304

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 14.2 km from Lake 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 USC00085076 (Lisbon). Public domain.