Colfax climate

Colfax Frost Dates and Growing Season

NOAA 1991-2020 normals for Menomonie, 21.5 km from Colfax, elevation 780 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Menomonie. 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 1, a growing season of about 143 days.

Median at 36°F
last May 21, first September 23
Median at 32°F
last May 9, first October 1
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 26May 23May 21May 19May 16May 12May 7
32°FMay 24May 19May 16May 13May 9May 7May 4May 1Apr 27
28°FMay 12May 8May 4May 2Apr 30Apr 26Apr 23Apr 19Apr 15
24°FMay 3Apr 28Apr 23Apr 20Apr 17Apr 14Apr 11Apr 6Apr 2
20°FApr 21Apr 15Apr 11Apr 8Apr 6Apr 4Apr 2Mar 30Mar 24
16°FApr 12Apr 7Apr 4Apr 2Mar 31Mar 28Mar 25Mar 21Mar 16

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 9Sep 14Sep 17Sep 20Sep 23Sep 26Sep 29Oct 1Oct 5
32°FSep 19Sep 23Sep 26Sep 29Oct 1Oct 4Oct 6Oct 9Oct 14
28°FSep 26Oct 1Oct 4Oct 7Oct 10Oct 13Oct 16Oct 21Oct 25
24°FOct 6Oct 12Oct 17Oct 20Oct 23Oct 26Oct 29Nov 1Nov 4
20°FOct 19Oct 25Oct 28Oct 30Nov 1Nov 3Nov 6Nov 10Nov 15
16°FOct 31Nov 2Nov 5Nov 8Nov 11Nov 14Nov 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°F142137132127123120115111104
32°F163155151147143139135130124
28°F183177172168164160156150143
24°F206200195192187183179173166
20°F228221216211207203199193186
16°F245238232229225221218213207

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
8,036
Cooling degree days, base 65°F
498
Growing degree days, base 40°F
4,276
Growing degree days, base 45°F
3,277
Growing degree days, base 50°F
2,395
Growing degree days, base 55°F
1,632
Growing degree days, base 60°F
993

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,57300
February1,30600
March1,06607
April622252
May29121229
June64104491
July14188638
August32134567
September18945323
October547380
November95607
December1,37600

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 21.5 km from Colfax. 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 USC00475335 (Menomonie). Public domain.