Otho climate

Otho Frost Dates and Growing Season

NOAA 1991-2020 normals for Ft Dodge 5NNW, 18.1 km from Otho, elevation 1115 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ft Dodge 5NNW. 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 28 and the first fall freeze around October 8, a growing season of about 162 days.

Median at 36°F
last May 6, first September 30
Median at 32°F
last April 28, first October 8
Median at 28°F
last April 17, first October 19

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 10May 8May 6May 3May 1Apr 29Apr 24
32°FMay 9May 5May 3Apr 30Apr 28Apr 25Apr 22Apr 18Apr 13
28°FMay 1Apr 27Apr 23Apr 20Apr 17Apr 15Apr 12Apr 8Apr 4
24°FApr 22Apr 17Apr 14Apr 10Apr 8Apr 5Apr 2Mar 31Mar 23
20°FApr 15Apr 10Apr 6Apr 3Apr 1Mar 29Mar 24Mar 18Mar 13
16°FApr 5Apr 1Mar 28Mar 25Mar 21Mar 17Mar 14Mar 10Mar 5

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 17Sep 21Sep 24Sep 27Sep 30Oct 1Oct 4Oct 7Oct 12
32°FSep 24Sep 29Oct 2Oct 5Oct 8Oct 11Oct 15Oct 18Oct 22
28°FOct 3Oct 9Oct 14Oct 17Oct 19Oct 23Oct 25Oct 28Nov 1
24°FOct 15Oct 20Oct 24Oct 27Oct 29Nov 1Nov 3Nov 6Nov 11
20°FOct 24Oct 30Nov 1Nov 3Nov 6Nov 9Nov 11Nov 16Nov 20
16°FNov 1Nov 5Nov 9Nov 12Nov 14Nov 17Nov 20Nov 24Nov 30

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°F161155151148144142138134127
32°F182174170165162158154150144
28°F203196191187183179176170164
24°F224216211207203199194190185
20°F243236230226221216212207200
16°F261254248243239234229225215

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
7,388
Cooling degree days, base 65°F
677
Growing degree days, base 40°F
4,776
Growing degree days, base 45°F
3,721
Growing degree days, base 50°F
2,777
Growing degree days, base 55°F
1,951
Growing degree days, base 60°F
1,246

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,50500
February1,23201
March966016
April549379
May23539293
June33154572
July7235693
August20172617
September14465380
October4888116
November897012
December1,31100

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 18.1 km from Otho. 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 USC00132999 (Ft Dodge 5NNW). Public domain.