Harbor Beach climate

Harbor Beach Frost Dates and Growing Season

NOAA 1991-2020 normals for Harbor Beach 1 Sse, 1.6 km from Harbor Beach, elevation 595 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Harbor Beach 1 Sse. 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 2 and the first fall freeze around October 24, a growing season of about 173 days.

Median at 36°F
last May 15, first October 11
Median at 32°F
last May 2, first October 24
Median at 28°F
last April 20, first November 3

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 28May 24May 21May 18May 15May 11May 8May 5May 1
32°FMay 17May 11May 8May 5May 2Apr 30Apr 27Apr 24Apr 19
28°FMay 4Apr 30Apr 27Apr 23Apr 20Apr 17Apr 14Apr 11Apr 7
24°FApr 22Apr 18Apr 14Apr 11Apr 8Apr 5Apr 2Mar 31Mar 24
20°FApr 12Apr 5Apr 2Mar 31Mar 28Mar 24Mar 21Mar 17Mar 13
16°FMar 31Mar 27Mar 23Mar 20Mar 17Mar 15Mar 13Mar 9Mar 4

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 29Oct 1Oct 5Oct 8Oct 11Oct 14Oct 17Oct 19Oct 24
32°FOct 7Oct 14Oct 18Oct 21Oct 24Oct 26Oct 29Nov 1Nov 6
28°FOct 21Oct 26Oct 30Nov 1Nov 3Nov 6Nov 10Nov 13Nov 18
24°FOct 31Nov 5Nov 9Nov 12Nov 16Nov 19Nov 22Nov 26Dec 1
20°FNov 8Nov 16Nov 21Nov 24Nov 27Nov 30Dec 3Dec 7Dec 14
16°FNov 21Nov 27Dec 1Dec 3Dec 7Dec 10Dec 15Dec 19Dec 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°F168161157152148144140136129
32°F192185180176173169165161155
28°F217211206202198193190186178
24°F242236231226222217213207201
20°F266259254248244240236230223
16°F286278273268264259254248241

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
7,461
Cooling degree days, base 65°F
352
Growing degree days, base 40°F
3,940
Growing degree days, base 45°F
2,940
Growing degree days, base 50°F
2,081
Growing degree days, base 55°F
1,357
Growing degree days, base 60°F
770

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,32400
February1,17700
March1,05604
April718124
May41012142
June14058371
July34130561
August35109539
September16140334
October479395
November80009
December1,12800

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 1.6 km from Harbor Beach. 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 USC00203585 (Harbor Beach 1 Sse). Public domain.