Dubois climate

Dubois Frost Dates and Growing Season

NOAA 1991-2020 normals for Dubois Exp Stn, 7.9 km from Dubois, elevation 5450 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Dubois Exp Stn. 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 18 and the first fall freeze around September 30, a growing season of about 132 days.

Median at 36°F
last June 5, first September 18
Median at 32°F
last May 18, first September 30
Median at 28°F
last May 2, first October 12

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 22Jun 17Jun 13Jun 10Jun 5Jun 2May 30May 23May 18
32°FJun 9Jun 1May 27May 22May 18May 14May 11May 8May 3
28°FMay 17May 11May 8May 4May 2Apr 29Apr 26Apr 21Apr 16
24°FMay 2Apr 28Apr 24Apr 20Apr 17Apr 13Apr 10Apr 6Mar 31
20°FApr 17Apr 11Apr 7Apr 3Mar 31Mar 27Mar 21Mar 17Mar 10
16°FApr 2Mar 28Mar 23Mar 19Mar 16Mar 12Mar 9Mar 5Mar 2

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 4Sep 8Sep 12Sep 15Sep 18Sep 20Sep 23Sep 26Oct 1
32°FSep 14Sep 19Sep 24Sep 27Sep 30Oct 3Oct 6Oct 10Oct 16
28°FSep 27Oct 1Oct 5Oct 8Oct 12Oct 16Oct 19Oct 23Oct 26
24°FOct 7Oct 13Oct 17Oct 21Oct 23Oct 26Oct 29Nov 1Nov 6
20°FOct 18Oct 23Oct 27Oct 30Nov 1Nov 4Nov 7Nov 11Nov 17
16°FOct 26Oct 31Nov 3Nov 7Nov 10Nov 12Nov 15Nov 19Nov 25

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°F12311711210710298948982
32°F154147141136132127121116106
28°F184176170166162157152147139
24°F212204198193188184179174166
20°F238230224219215210205199192
16°F260252247242237233228221211

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
7,577
Cooling degree days, base 65°F
432
Growing degree days, base 40°F
4,015
Growing degree days, base 45°F
3,017
Growing degree days, base 50°F
2,158
Growing degree days, base 55°F
1,443
Growing degree days, base 60°F
867

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,32700
February1,11000
March93003
April606034
May3564160
June14245358
July21197642
August26158597
September18728307
October583057
November97701
December1,31300

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 7.9 km from Dubois. 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 USC00102707 (Dubois Exp Stn). Public domain.