Audubon County climate

Audubon County Frost Dates and Growing Season

NOAA 1991-2020 normals for Audubon, 2.8 km from Audubon County, elevation 1280 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Audubon. 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 2 and the first fall freeze around October 3, a growing season of about 154 days.

Median at 36°F
last May 10, first September 25
Median at 32°F
last May 2, first October 3
Median at 28°F
last April 22, first October 14

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 23May 19May 15May 12May 10May 7May 5May 2Apr 28
32°FMay 15May 9May 6May 4May 2Apr 30Apr 27Apr 23Apr 19
28°FMay 5May 1Apr 28Apr 25Apr 22Apr 19Apr 16Apr 13Apr 8
24°FApr 26Apr 21Apr 17Apr 14Apr 11Apr 8Apr 6Apr 3Mar 30
20°FApr 17Apr 12Apr 8Apr 5Apr 2Mar 31Mar 28Mar 23Mar 17
16°FApr 7Apr 2Mar 31Mar 27Mar 24Mar 20Mar 16Mar 12Mar 7

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 12Sep 16Sep 19Sep 22Sep 25Sep 28Oct 1Oct 4Oct 8
32°FSep 19Sep 24Sep 28Oct 1Oct 3Oct 5Oct 9Oct 13Oct 17
28°FSep 28Oct 2Oct 6Oct 11Oct 14Oct 16Oct 19Oct 22Oct 26
24°FOct 8Oct 15Oct 18Oct 21Oct 23Oct 26Oct 29Nov 1Nov 5
20°FOct 18Oct 24Oct 27Oct 30Nov 1Nov 3Nov 6Nov 10Nov 15
16°FOct 28Nov 1Nov 4Nov 7Nov 10Nov 13Nov 17Nov 21Nov 27

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°F154150145141137134129125118
32°F173166162158154150146141135
28°F192186181177173169164159153
24°F212205201197193189185181173
20°F232225219215212207203198191
16°F253245240236231226221216209

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
7,171
Cooling degree days, base 65°F
668
Growing degree days, base 40°F
4,802
Growing degree days, base 45°F
3,733
Growing degree days, base 50°F
2,779
Growing degree days, base 55°F
1,945
Growing degree days, base 60°F
1,236

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,44400
February1,18301
March920119
April532485
May22839298
June36151566
July9229685
August22172615
September14865377
October4867120
November884013
December1,28000

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 2.8 km from Audubon County. 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 USC00130385 (Audubon). Public domain.