Oshkosh climate

Oshkosh Frost Dates and Growing Season

NOAA 1991-2020 normals for Oshkosh, 0.4 km from Oshkosh, elevation 3390 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Oshkosh. 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 9 and the first fall freeze around October 2, a growing season of about 144 days.

Median at 36°F
last May 20, first September 24
Median at 32°F
last May 9, first October 2
Median at 28°F
last April 30, first October 10

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°FJun 2May 29May 25May 22May 20May 17May 14May 11May 7
32°FMay 22May 17May 14May 11May 9May 7May 4May 2Apr 28
28°FMay 13May 8May 5May 2Apr 30Apr 28Apr 25Apr 21Apr 16
24°FMay 3Apr 29Apr 26Apr 23Apr 20Apr 16Apr 13Apr 8Apr 4
20°FApr 25Apr 19Apr 15Apr 11Apr 7Apr 4Apr 1Mar 29Mar 23
16°FApr 15Apr 8Apr 4Mar 31Mar 28Mar 24Mar 20Mar 15Mar 9

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 10Sep 15Sep 19Sep 22Sep 24Sep 27Sep 29Oct 2Oct 5
32°FSep 20Sep 24Sep 28Sep 30Oct 2Oct 4Oct 7Oct 10Oct 14
28°FSep 28Oct 2Oct 5Oct 8Oct 10Oct 13Oct 16Oct 18Oct 22
24°FOct 6Oct 12Oct 15Oct 18Oct 20Oct 22Oct 24Oct 27Oct 30
20°FOct 15Oct 20Oct 23Oct 25Oct 27Oct 29Nov 1Nov 4Nov 8
16°FOct 22Oct 27Oct 30Nov 1Nov 4Nov 6Nov 9Nov 13Nov 18

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°F144137134130126123119114108
32°F162155151148144140137132125
28°F182174170166163159155150144
24°F201194189185182177173168162
20°F223216210205201197192187181
16°F245236231226221216211206199

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
6,583
Cooling degree days, base 65°F
776
Growing degree days, base 40°F
4,913
Growing degree days, base 45°F
3,804
Growing degree days, base 50°F
2,843
Growing degree days, base 55°F
2,026
Growing degree days, base 60°F
1,337

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,20600
February1,00002
March817018
April549169
May27626254
June50143544
July4294755
August14234685
September13076405
October5002104
November85509
December1,18400

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 0.4 km from Oshkosh. 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 USC00256385 (Oshkosh). Public domain.