Marathon County climate

Marathon County Frost Dates and Growing Season

NOAA 1991-2020 normals for Wausau Dwtn AP, 11 km from Marathon County, elevation 1181 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Wausau Dwtn 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 6 and the first fall freeze around October 4, a growing season of about 150 days.

Median at 36°F
last May 19, first September 25
Median at 32°F
last May 6, first October 4
Median at 28°F
last April 26, first October 16

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 31May 27May 25May 21May 19May 16May 12May 8May 4
32°FMay 21May 17May 12May 8May 6May 4May 1Apr 28Apr 24
28°FMay 10May 5May 1Apr 29Apr 26Apr 23Apr 20Apr 16Apr 12
24°FApr 29Apr 24Apr 21Apr 18Apr 15Apr 12Apr 9Apr 5Apr 1
20°FApr 20Apr 15Apr 11Apr 8Apr 4Apr 2Mar 31Mar 27Mar 22
16°FApr 12Apr 6Apr 3Apr 1Mar 30Mar 27Mar 23Mar 19Mar 13

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 12Sep 17Sep 20Sep 23Sep 25Sep 28Oct 1Oct 3Oct 7
32°FSep 21Sep 26Sep 29Oct 1Oct 4Oct 6Oct 9Oct 12Oct 18
28°FOct 1Oct 5Oct 9Oct 13Oct 16Oct 19Oct 23Oct 26Oct 31
24°FOct 14Oct 20Oct 24Oct 27Oct 30Nov 1Nov 4Nov 7Nov 13
20°FOct 27Nov 1Nov 3Nov 5Nov 8Nov 11Nov 14Nov 17Nov 21
16°FNov 4Nov 8Nov 11Nov 14Nov 17Nov 20Nov 22Nov 26Nov 30

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°F148142137133130126122117111
32°F170163158154150146142137130
28°F194187181177173169164158152
24°F217210205201197193189184178
20°F235229224220216212208204198
16°F252245240236232229225219213

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
8,174
Cooling degree days, base 65°F
422
Growing degree days, base 40°F
4,073
Growing degree days, base 45°F
3,096
Growing degree days, base 50°F
2,238
Growing degree days, base 55°F
1,498
Growing degree days, base 60°F
885

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,55800
February1,30300
March1,08208
April660141
May30521222
June7888461
July21161604
August40114539
September20935293
October580266
November96605
December1,37300

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 11 km from Marathon County. 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 USW00014897 (Wausau Dwtn AP). Public domain.