Chippewa County climate

Chippewa County Frost Dates and Growing Season

NOAA 1991-2020 normals for Jim Falls 3NW, 4.3 km from Chippewa County, elevation 1070 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Jim Falls 3NW. 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 8, a growing season of about 158 days.

Median at 36°F
last May 12, first September 28
Median at 32°F
last May 1, first October 8
Median at 28°F
last April 21, first October 20

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 26May 21May 18May 15May 12May 9May 7May 4Apr 30
32°FMay 16May 10May 7May 4May 1Apr 29Apr 26Apr 22Apr 17
28°FMay 3Apr 30Apr 27Apr 24Apr 21Apr 17Apr 15Apr 11Apr 6
24°FApr 24Apr 20Apr 16Apr 13Apr 10Apr 7Apr 5Apr 2Mar 30
20°FApr 16Apr 10Apr 7Apr 5Apr 3Apr 1Mar 30Mar 26Mar 20
16°FApr 8Apr 4Apr 1Mar 31Mar 27Mar 24Mar 20Mar 16Mar 11

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 15Sep 19Sep 22Sep 25Sep 28Oct 1Oct 4Oct 7Oct 11
32°FSep 22Sep 28Oct 1Oct 5Oct 8Oct 11Oct 14Oct 18Oct 22
28°FOct 1Oct 9Oct 14Oct 17Oct 20Oct 23Oct 26Oct 30Nov 4
24°FOct 18Oct 23Oct 27Oct 31Nov 1Nov 4Nov 7Nov 11Nov 17
20°FOct 29Nov 1Nov 5Nov 8Nov 11Nov 14Nov 17Nov 21Nov 27
16°FNov 5Nov 9Nov 12Nov 15Nov 19Nov 22Nov 25Nov 29Dec 4

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°F156150145141138134130125119
32°F178171166162158154150145138
28°F203196191186181177172167159
24°F225218212208203199194189181
20°F243236231226223218214209203
16°F259252247241237233229224217

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
7,946
Cooling degree days, base 65°F
432
Growing degree days, base 40°F
4,245
Growing degree days, base 45°F
3,238
Growing degree days, base 50°F
2,350
Growing degree days, base 55°F
1,579
Growing degree days, base 60°F
929

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,54500
February1,29600
March1,061014
April638147
May28716230
June5980471
July14166617
August31122556
September18045326
October541381
November94208
December1,35300

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 4.3 km from Chippewa 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 USC00474027 (Jim Falls 3NW). Public domain.