Sault Ste. Marie climate

Sault Ste. Marie Frost Dates and Growing Season

NOAA 1991-2020 normals for Sault Ste Marie Sanderson Fld, 2 km from Sault Ste. Marie, elevation 722 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Sault Ste Marie Sanderson Fld. 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 9 and the first fall freeze around October 11, a growing season of about 151 days.

Median at 36°F
last May 26, first September 29
Median at 32°F
last May 9, first October 11
Median at 28°F
last April 27, first October 26

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°FJun 11Jun 5Jun 1May 30May 26May 23May 21May 17May 10
32°FMay 27May 21May 17May 13May 9May 6May 2Apr 30Apr 27
28°FMay 10May 4May 1Apr 29Apr 27Apr 24Apr 21Apr 18Apr 14
24°FApr 26Apr 22Apr 19Apr 16Apr 14Apr 12Apr 9Apr 6Apr 3
20°FApr 19Apr 15Apr 12Apr 9Apr 7Apr 5Apr 2Apr 1Mar 27
16°FApr 13Apr 9Apr 5Apr 3Apr 1Mar 31Mar 28Mar 24Mar 19

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

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°F145137131128125121116110102
32°F172165159155151146142137129
28°F199193189184179175170166158
24°F223217213209206201198194188
20°F240233229225222218215211204
16°F254247243239235231227223218

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
8,457
Cooling degree days, base 65°F
236
Growing degree days, base 40°F
3,528
Growing degree days, base 45°F
2,593
Growing degree days, base 50°F
1,795
Growing degree days, base 55°F
1,120
Growing degree days, base 60°F
588

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,51300
February1,32000
March1,18702
April770013
May4077139
June15033337
July6091496
August6079484
September22525267
October581154
November90804
December1,27700

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 km from Sault Ste. Marie. 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 USW00014847 (Sault Ste Marie Sanderson Fld). Public domain.