Somers climate

Somers Frost Dates and Growing Season

NOAA 1991-2020 normals for Kenosha Rgnl AP, 5.5 km from Somers, elevation 743 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Kenosha 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 28 and the first fall freeze around October 19, a growing season of about 174 days.

Median at 36°F
last May 8, first October 7
Median at 32°F
last April 28, first October 19
Median at 28°F
last April 15, first October 30

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

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°F169161156151148144140136128
32°F194186182178174169164159153
28°F215210205200196192187182174
24°F240233228224219215211206199
20°F264255251246241238235229220
16°F286277271266261258253247240

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
6,447
Cooling degree days, base 65°F
722
Growing degree days, base 40°F
4,978
Growing degree days, base 45°F
3,849
Growing degree days, base 50°F
2,862
Growing degree days, base 55°F
2,011
Growing degree days, base 60°F
1,292

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,27600
February1,06802
March880121
April543470
May25438271
June54138534
July9249705
August10201656
September11179421
October39411156
November749024
December1,10002

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 5.5 km from Somers. 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 USW00004845 (Kenosha Rgnl AP). Public domain.