Goodwill climate

Goodwill Frost Dates and Growing Season

NOAA 1991-2020 normals for Sisseton, 11.2 km from Goodwill, elevation 1209 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sisseton. 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 3, a growing season of about 151 days.

Median at 36°F
last May 13, first September 26
Median at 32°F
last May 4, first October 3
Median at 28°F
last April 26, 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 26May 22May 18May 16May 13May 10May 7May 5Apr 30
32°FMay 17May 12May 8May 6May 4May 1Apr 29Apr 26Apr 21
28°FMay 9May 5May 1Apr 28Apr 26Apr 23Apr 19Apr 16Apr 11
24°FApr 30Apr 26Apr 22Apr 19Apr 17Apr 14Apr 10Apr 7Apr 3
20°FApr 22Apr 18Apr 15Apr 12Apr 9Apr 5Apr 3Apr 1Mar 25
16°FApr 16Apr 11Apr 8Apr 5Apr 2Mar 31Mar 27Mar 22Mar 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 13Sep 17Sep 20Sep 23Sep 26Sep 28Sep 30Oct 3Oct 7
32°FSep 22Sep 26Sep 29Oct 1Oct 3Oct 5Oct 8Oct 12Oct 17
28°FOct 1Oct 4Oct 7Oct 10Oct 14Oct 16Oct 20Oct 23Oct 27
24°FOct 8Oct 14Oct 18Oct 22Oct 24Oct 27Oct 30Nov 2Nov 7
20°FOct 20Oct 24Oct 28Oct 31Nov 2Nov 5Nov 8Nov 12Nov 17
16°FOct 28Nov 1Nov 5Nov 8Nov 11Nov 13Nov 16Nov 20Nov 24

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°F150146141138134130126122116
32°F168162157154151147144139132
28°F189183178173169166162157150
24°F208202197193189185181176169
20°F227220214210207203198193186
16°F244236230226222218213209203

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
8,195
Cooling degree days, base 65°F
575
Growing degree days, base 40°F
4,394
Growing degree days, base 45°F
3,398
Growing degree days, base 50°F
2,512
Growing degree days, base 55°F
1,740
Growing degree days, base 60°F
1,090

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,60300
February1,32900
March1,09106
April641148
May27928252
June54113509
July12212665
August26162601
September17454341
October566584
November99807
December1,42300

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 11.2 km from Goodwill. 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 USC00397742 (Sisseton). Public domain.