Codington County climate

Codington County Frost Dates and Growing Season

NOAA 1991-2020 normals for Rauville 2 W, 3.2 km from Codington County, elevation 1737 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Rauville 2 W. 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 7 and the first fall freeze around September 28, a growing season of about 143 days.

Median at 36°F
last May 15, first September 19
Median at 32°F
last May 7, first September 28
Median at 28°F
last April 28, first October 8

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 29May 25May 21May 18May 15May 13May 11May 8May 4
32°FMay 20May 15May 12May 9May 7May 4May 2Apr 30Apr 24
28°FMay 11May 6May 3Apr 30Apr 28Apr 24Apr 21Apr 18Apr 13
24°FMay 2Apr 28Apr 24Apr 21Apr 18Apr 15Apr 12Apr 9Apr 5
20°FApr 24Apr 19Apr 16Apr 11Apr 9Apr 6Apr 4Apr 1Mar 25
16°FApr 17Apr 11Apr 7Apr 4Apr 1Mar 30Mar 25Mar 21Mar 15

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 7Sep 11Sep 14Sep 17Sep 19Sep 22Sep 24Sep 27Oct 2
32°FSep 16Sep 20Sep 22Sep 25Sep 28Oct 1Oct 3Oct 8Oct 13
28°FSep 24Sep 29Oct 3Oct 5Oct 8Oct 12Oct 15Oct 20Oct 23
24°FOct 5Oct 10Oct 15Oct 19Oct 22Oct 25Oct 28Oct 31Nov 4
20°FOct 18Oct 23Oct 27Oct 29Nov 1Nov 3Nov 5Nov 9Nov 14
16°FOct 28Nov 1Nov 3Nov 5Nov 8Nov 11Nov 14Nov 17Nov 22

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°F141136132129125122119114107
32°F160154151147143140136132126
28°F183177172167163159155150144
24°F205198192188184180176171164
20°F223217212208204200195190183
16°F241234229225220217213208201

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
8,563
Cooling degree days, base 65°F
466
Growing degree days, base 40°F
4,141
Growing degree days, base 45°F
3,171
Growing degree days, base 50°F
2,309
Growing degree days, base 55°F
1,562
Growing degree days, base 60°F
941

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,66000
February1,38200
March1,14007
April678037
May30322228
June6787470
July13191643
August37133561
September20630291
October600369
November1,02504
December1,45400

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 3.2 km from Codington 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 USC00396969 (Rauville 2 W). Public domain.