Waunakee climate

Waunakee Frost Dates and Growing Season

NOAA 1991-2020 normals for Madison Dane Rgnl AP, 10.6 km from Waunakee, elevation 866 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Madison Dane 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 May 1 and the first fall freeze around October 10, a growing season of about 160 days.

Median at 36°F
last May 13, first September 29
Median at 32°F
last May 1, first October 10
Median at 28°F
last April 20, first October 22

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 29May 23May 19May 16May 13May 10May 6May 2Apr 29
32°FMay 16May 11May 7May 3May 1Apr 29Apr 25Apr 22Apr 16
28°FMay 5Apr 30Apr 26Apr 23Apr 20Apr 17Apr 13Apr 10Apr 5
24°FApr 22Apr 17Apr 13Apr 10Apr 7Apr 4Apr 2Mar 31Mar 25
20°FApr 12Apr 6Apr 3Apr 1Mar 30Mar 26Mar 22Mar 19Mar 14
16°FApr 2Mar 30Mar 25Mar 22Mar 19Mar 17Mar 14Mar 11Mar 6

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 17Sep 21Sep 24Sep 27Sep 29Oct 2Oct 4Oct 7Oct 12
32°FSep 26Sep 30Oct 4Oct 7Oct 10Oct 12Oct 15Oct 18Oct 24
28°FOct 6Oct 12Oct 16Oct 19Oct 22Oct 25Oct 28Oct 31Nov 4
24°FOct 19Oct 25Oct 29Oct 31Nov 2Nov 5Nov 8Nov 12Nov 17
20°FNov 1Nov 3Nov 6Nov 10Nov 13Nov 15Nov 18Nov 22Nov 26
16°FNov 6Nov 12Nov 15Nov 19Nov 22Nov 25Nov 28Dec 1Dec 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°F158151147143139135131126119
32°F179172167164160156153147140
28°F203196191187182178174169162
24°F226220215211207204199194185
20°F249242238233229225220215209
16°F267260255251247243238233225

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
7,138
Cooling degree days, base 65°F
627
Growing degree days, base 40°F
4,670
Growing degree days, base 45°F
3,606
Growing degree days, base 50°F
2,669
Growing degree days, base 55°F
1,860
Growing degree days, base 60°F
1,174

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,41300
February1,17500
March951115
April562265
May25236272
June47137540
July9221677
August20166611
September15159366
October4806109
November848013
December1,23201

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 10.6 km from Waunakee. 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 USW00014837 (Madison Dane Rgnl AP). Public domain.