Gurnee climate

Gurnee Frost Dates and Growing Season

NOAA 1991-2020 normals for Chicago Waukegan Rgnl AP, 5.9 km from Gurnee, elevation 727 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Chicago Waukegan Rgnl AP. 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 30 and the first fall freeze around October 21, a growing season of about 173 days.

Median at 36°F
last May 12, first October 10
Median at 32°F
last April 30, first October 21
Median at 28°F
last April 16, first November 1

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 27May 23May 19May 15May 12May 8May 5May 1Apr 28
32°FMay 16May 10May 6May 2Apr 30Apr 26Apr 23Apr 20Apr 14
28°FMay 2Apr 27Apr 23Apr 20Apr 16Apr 13Apr 10Apr 6Apr 2
24°FApr 20Apr 13Apr 9Apr 6Apr 3Apr 1Mar 30Mar 26Mar 20
20°FApr 5Apr 1Mar 30Mar 27Mar 24Mar 20Mar 17Mar 13Mar 9
16°FMar 29Mar 24Mar 20Mar 17Mar 14Mar 11Mar 7Mar 3Feb 27

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

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°F170164159154150146142136129
32°F194187182177173169165160152
28°F217211205201197192187181173
24°F241234229224220217212207199
20°F264255249244241237232227220
16°F283275269264259255250245238

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
6,688
Cooling degree days, base 65°F
626
Growing degree days, base 40°F
4,725
Growing degree days, base 45°F
3,624
Growing degree days, base 50°F
2,670
Growing degree days, base 55°F
1,846
Growing degree days, base 60°F
1,162

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,28800
February1,08502
March912117
April581460
May29827228
June73113491
July13218669
August12184637
September12171404
October4188139
November767021
December1,12101

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 5.9 km from Gurnee. 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 USW00014880 (Chicago Waukegan Rgnl AP). Public domain.