Hoffman climate

Hoffman Frost Dates and Growing Season

NOAA 1991-2020 normals for Morris W Cntrl Rsch & Outreach, 27.3 km from Hoffman, elevation 1140 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Morris W Cntrl Rsch & Outreach. 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 4 and the first fall freeze around October 1, a growing season of about 150 days.

Median at 36°F
last May 13, first September 23
Median at 32°F
last May 4, first October 1
Median at 28°F
last April 24, first October 11

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 28May 22May 19May 16May 13May 11May 8May 5May 1
32°FMay 17May 12May 9May 6May 4May 1Apr 30Apr 26Apr 21
28°FMay 7May 3Apr 30Apr 28Apr 24Apr 21Apr 18Apr 14Apr 9
24°FApr 29Apr 23Apr 19Apr 16Apr 13Apr 10Apr 7Apr 5Apr 1
20°FApr 20Apr 15Apr 11Apr 8Apr 6Apr 3Apr 1Mar 29Mar 22
16°FApr 13Apr 7Apr 5Apr 2Mar 31Mar 28Mar 23Mar 19Mar 14

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 18Sep 20Sep 23Sep 25Sep 28Sep 30Oct 4
32°FSep 19Sep 23Sep 26Sep 29Oct 1Oct 3Oct 5Oct 10Oct 17
28°FSep 27Oct 1Oct 4Oct 7Oct 11Oct 14Oct 18Oct 22Oct 25
24°FOct 5Oct 11Oct 16Oct 20Oct 23Oct 26Oct 29Nov 1Nov 5
20°FOct 17Oct 23Oct 27Oct 30Nov 1Nov 4Nov 7Nov 11Nov 15
16°FOct 29Nov 1Nov 4Nov 7Nov 10Nov 12Nov 15Nov 18Nov 23

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°F149143139135132128123119112
32°F169162158154150146142137131
28°F191184179174170166161157149
24°F211204199195191187182177170
20°F229221217212209205201196189
16°F244237232227223220215211204

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
8,757
Cooling degree days, base 65°F
498
Growing degree days, base 40°F
4,173
Growing degree days, base 45°F
3,214
Growing degree days, base 50°F
2,360
Growing degree days, base 55°F
1,617
Growing degree days, base 60°F
989

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,71000
February1,43400
March1,16904
April679141
May29829242
June61113503
July18182629
August37127555
September19643315
October606370
November1,05004
December1,50200

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 27.3 km from Hoffman. 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 USC00215638 (Morris W Cntrl Rsch & Outreach). Public domain.