Silver Bay climate

Silver Bay Frost Dates and Growing Season

NOAA 1991-2020 normals for Wolf Ridge Elc, 17.6 km from Silver Bay, elevation 1400 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Wolf Ridge Elc. 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 15 and the first fall freeze around October 1, a growing season of about 137 days.

Median at 36°F
last May 30, first September 20
Median at 32°F
last May 15, first October 1
Median at 28°F
last May 2, first October 10

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 6Jun 3Jun 1May 30May 26May 23May 19May 14
32°FMay 31May 26May 22May 19May 15May 11May 7May 4Apr 30
28°FMay 20May 13May 8May 5May 2Apr 30Apr 28Apr 24Apr 19
24°FMay 5May 1Apr 29Apr 26Apr 22Apr 19Apr 16Apr 13Apr 8
20°FApr 28Apr 23Apr 19Apr 17Apr 14Apr 10Apr 8Apr 6Apr 2
16°FApr 19Apr 15Apr 11Apr 8Apr 6Apr 4Apr 2Mar 31Mar 24

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

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°F13412712211711410910510093
32°F157150145141137133128123116
28°F182175170165160156152146139
24°F204197192187183179174169161
20°F223216211207203198194189183
16°F236230225221218214211207200

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
9,634
Cooling degree days, base 65°F
175
Growing degree days, base 40°F
3,147
Growing degree days, base 45°F
2,282
Growing degree days, base 50°F
1,543
Growing degree days, base 55°F
935
Growing degree days, base 60°F
469

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,70200
February1,43600
March1,24001
April836010
May480499
June18725297
July7281474
August8854431
September29712199
October694031
November1,10001
December1,50300

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 17.6 km from Silver Bay. 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 USC00219134 (Wolf Ridge Elc). Public domain.