Mobridge climate

Mobridge Frost Dates and Growing Season

NOAA 1991-2020 normals for Mobridge Muni AP, 1.9 km from Mobridge, elevation 1715 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Mobridge Muni AP. 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 5 and the first fall freeze around October 4, a growing season of about 150 days.

Median at 36°F
last May 16, first September 26
Median at 32°F
last May 5, first October 4
Median at 28°F
last April 28, 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°FMay 30May 25May 22May 19May 16May 14May 11May 8May 4
32°FMay 20May 15May 11May 8May 5May 3May 1Apr 28Apr 23
28°FMay 10May 5May 3Apr 30Apr 28Apr 25Apr 21Apr 18Apr 13
24°FMay 2Apr 28Apr 24Apr 21Apr 18Apr 15Apr 11Apr 8Apr 3
20°FApr 24Apr 19Apr 15Apr 12Apr 9Apr 6Apr 3Mar 31Mar 25
16°FApr 17Apr 10Apr 7Apr 4Apr 1Mar 30Mar 24Mar 19Mar 12

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 13Sep 18Sep 22Sep 24Sep 26Sep 29Oct 1Oct 4Oct 8
32°FSep 21Sep 26Sep 30Oct 2Oct 4Oct 7Oct 10Oct 13Oct 17
28°FSep 29Oct 3Oct 7Oct 9Oct 12Oct 15Oct 18Oct 21Oct 26
24°FOct 7Oct 12Oct 17Oct 20Oct 22Oct 25Oct 28Nov 1Nov 5
20°FOct 18Oct 24Oct 27Oct 30Nov 1Nov 4Nov 6Nov 10Nov 14
16°FOct 27Nov 1Nov 3Nov 6Nov 9Nov 12Nov 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°F150144140136133129126121114
32°F169163157154150146143139132
28°F188181176172169165161156149
24°F206200195190187182178174167
20°F226218212208204200196191183
16°F243236230225220216212206200

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
7,549
Cooling degree days, base 65°F
812
Growing degree days, base 40°F
4,828
Growing degree days, base 45°F
3,785
Growing degree days, base 50°F
2,857
Growing degree days, base 55°F
2,049
Growing degree days, base 60°F
1,366

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,49600
February1,22800
March980012
April577164
May25727264
June52139538
July6300759
August13254707
September13884404
October5207104
November94506
December1,33900

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 1.9 km from Mobridge. 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 USW00094052 (Mobridge Muni AP). Public domain.