Ashwaubenon climate

Ashwaubenon Frost Dates and Growing Season

NOAA 1991-2020 normals for Green Bay, 3.7 km from Ashwaubenon, elevation 682 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Green Bay. 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 9, a growing season of about 161 days.

Median at 36°F
last May 13, first September 29
Median at 32°F
last April 30, first October 9
Median at 28°F
last April 17, 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 27May 23May 19May 16May 13May 9May 6May 2Apr 29
32°FMay 16May 11May 7May 4Apr 30Apr 29Apr 25Apr 22Apr 16
28°FMay 4Apr 29Apr 24Apr 21Apr 17Apr 15Apr 11Apr 7Apr 3
24°FApr 21Apr 16Apr 12Apr 8Apr 5Apr 3Apr 1Mar 28Mar 22
20°FApr 11Apr 6Apr 3Mar 31Mar 29Mar 26Mar 22Mar 18Mar 13
16°FApr 4Mar 31Mar 27Mar 24Mar 20Mar 17Mar 14Mar 10Mar 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 16Sep 20Sep 24Sep 26Sep 29Oct 1Oct 4Oct 7Oct 12
32°FSep 24Sep 29Oct 3Oct 6Oct 9Oct 12Oct 16Oct 21Oct 26
28°FOct 6Oct 11Oct 16Oct 21Oct 24Oct 28Nov 1Nov 3Nov 9
24°FOct 21Oct 28Nov 1Nov 2Nov 6Nov 9Nov 12Nov 17Nov 22
20°FNov 1Nov 6Nov 10Nov 14Nov 17Nov 20Nov 23Nov 26Dec 1
16°FNov 10Nov 16Nov 19Nov 23Nov 25Nov 28Dec 1Dec 4Dec 10

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°F158152148144140136132128121
32°F181174169165161157153149141
28°F210203197192187183179172165
24°F234227222217213209204198189
20°F254245241237232228224219212
16°F269263257253249245240235229

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
7,505
Cooling degree days, base 65°F
508
Growing degree days, base 40°F
4,349
Growing degree days, base 45°F
3,323
Growing degree days, base 50°F
2,428
Growing degree days, base 55°F
1,657
Growing degree days, base 60°F
1,010

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,44800
February1,22900
March1,01909
April622144
May28826234
June65107492
July14186637
August27137575
September16947337
October507491
November86409
December1,25400

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 3.7 km from Ashwaubenon. 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 USW00014898 (Green Bay). Public domain.