Concord climate

Concord Frost Dates and Growing Season

NOAA 1991-2020 normals for Oconomowoc Wwtp, 8.4 km from Concord, elevation 858 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Oconomowoc Wwtp. 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 12, a growing season of about 164 days.

Median at 36°F
last May 12, first October 2
Median at 32°F
last April 30, first October 12
Median at 28°F
last April 19, first October 24

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 28May 24May 20May 16May 12May 9May 6May 2Apr 27
32°FMay 17May 10May 6May 3Apr 30Apr 27Apr 24Apr 21Apr 16
28°FMay 3Apr 28Apr 25Apr 21Apr 19Apr 15Apr 13Apr 9Apr 5
24°FApr 21Apr 16Apr 12Apr 9Apr 6Apr 4Apr 2Mar 31Mar 23
20°FApr 11Apr 5Apr 3Mar 31Mar 28Mar 25Mar 21Mar 18Mar 13
16°FApr 1Mar 29Mar 25Mar 21Mar 18Mar 16Mar 13Mar 9Mar 4

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

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°F162155150146142139134129121
32°F185178173168164160156151143
28°F206199195190186182177173165
24°F228222216213209206201196188
20°F251244238233230226222216210
16°F269261257253248245240235229

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
7,089
Cooling degree days, base 65°F
643
Growing degree days, base 40°F
4,717
Growing degree days, base 45°F
3,651
Growing degree days, base 50°F
2,708
Growing degree days, base 55°F
1,891
Growing degree days, base 60°F
1,198

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,40700
February1,17601
March957115
April570367
May25737270
June52133531
July9218674
August17177625
September13667388
October4637121
November831016
December1,21401

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 8.4 km from Concord. 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 USC00476200 (Oconomowoc Wwtp). Public domain.