Colfax climate

Colfax Frost Dates and Growing Season

NOAA 1991-2020 normals for Frankfort Disposal, 17.8 km from Colfax, elevation 824 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Frankfort Disposal. 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 April 21 and the first fall freeze around October 21, a growing season of about 181 days.

Median at 36°F
last May 2, first October 10
Median at 32°F
last April 21, first October 21
Median at 28°F
last April 7, first November 1

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 17May 13May 9May 5May 2Apr 30Apr 26Apr 23Apr 19
32°FMay 7May 1Apr 28Apr 24Apr 21Apr 19Apr 16Apr 12Apr 7
28°FApr 23Apr 18Apr 14Apr 11Apr 7Apr 5Apr 2Mar 31Mar 26
24°FApr 12Apr 5Apr 2Mar 31Mar 28Mar 25Mar 21Mar 17Mar 11
20°FApr 1Mar 28Mar 23Mar 19Mar 16Mar 13Mar 9Mar 6Feb 28
16°FMar 23Mar 17Mar 14Mar 10Mar 7Mar 4Mar 1Feb 24Feb 17

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 27Oct 1Oct 4Oct 7Oct 10Oct 12Oct 15Oct 18Oct 22
32°FOct 6Oct 12Oct 15Oct 18Oct 21Oct 23Oct 26Oct 29Nov 1
28°FOct 19Oct 24Oct 27Oct 30Nov 1Nov 3Nov 5Nov 8Nov 14
24°FOct 31Nov 3Nov 6Nov 9Nov 11Nov 15Nov 18Nov 23Nov 30
20°FNov 7Nov 11Nov 15Nov 19Nov 23Nov 27Dec 1Dec 6Dec 12
16°FNov 14Nov 20Nov 26Dec 1Dec 3Dec 7Dec 12Dec 17Dec 24

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°F178172167163159155151145139
32°F201194188184181177173168160
28°F226219213210206202197192186
24°F253244238234230225221215209
20°F276269262256251246241236229
16°F296287280275270266261254245

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
5,718
Cooling degree days, base 65°F
899
Growing degree days, base 40°F
5,607
Growing degree days, base 45°F
4,399
Growing degree days, base 50°F
3,326
Growing degree days, base 55°F
2,381
Growing degree days, base 60°F
1,570

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,19902
February97804
March770240
April4129140
May15972386
June21201630
July3270732
August6226685
September80104476
October34916190
November699037
December1,04005

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 17.8 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 USC00123082 (Frankfort Disposal). Public domain.