Forest County climate

Forest County Frost Dates and Growing Season

NOAA 1991-2020 normals for Laona 6 Sw, 17.3 km from Forest County, elevation 1695 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Laona 6 Sw. 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 19 and the first fall freeze around September 29, a growing season of about 131 days.

Median at 36°F
last May 31, first September 19
Median at 32°F
last May 19, first September 29
Median at 28°F
last May 6, first October 9

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

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 3Sep 8Sep 12Sep 16Sep 19Sep 22Sep 25Sep 28Oct 1
32°FSep 15Sep 20Sep 24Sep 26Sep 29Oct 1Oct 4Oct 7Oct 13
28°FSep 24Sep 30Oct 3Oct 6Oct 9Oct 13Oct 16Oct 21Oct 25
24°FOct 5Oct 11Oct 17Oct 21Oct 25Oct 28Nov 1Nov 3Nov 8
20°FOct 22Oct 28Oct 31Nov 2Nov 4Nov 7Nov 11Nov 14Nov 19
16°FNov 1Nov 4Nov 7Nov 10Nov 12Nov 15Nov 18Nov 21Nov 26

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°F128121117112108104989385
32°F151144139136131127123118111
28°F175168163160155151146141134
24°F201193188183179175170165157
20°F224216210207202198194189183
16°F238232227223219215211206199

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
9,331
Cooling degree days, base 65°F
146
Growing degree days, base 40°F
3,196
Growing degree days, base 45°F
2,304
Growing degree days, base 50°F
1,541
Growing degree days, base 55°F
909
Growing degree days, base 60°F
434

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,64800
February1,40000
March1,21105
April791020
May4168143
June17129315
July8560440
August11738387
September31610186
October669143
November1,05602
December1,45200

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 17.3 km from Forest 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 USC00474582 (Laona 6 Sw). Public domain.