Merrill climate

Merrill Frost Dates and Growing Season

NOAA 1991-2020 normals for Saginaw Mbs Intl AP, 24.3 km from Merrill, elevation 660 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Saginaw Mbs Intl 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 April 26 and the first fall freeze around October 17, a growing season of about 172 days.

Median at 36°F
last May 7, first October 5
Median at 32°F
last April 26, first October 17
Median at 28°F
last April 15, first October 31

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 22May 18May 14May 10May 7May 4Apr 30Apr 28Apr 24
32°FMay 13May 7May 3Apr 29Apr 26Apr 23Apr 21Apr 17Apr 13
28°FApr 30Apr 24Apr 21Apr 18Apr 15Apr 12Apr 8Apr 5Apr 1
24°FApr 17Apr 12Apr 8Apr 6Apr 4Apr 2Mar 31Mar 26Mar 20
20°FApr 7Apr 3Mar 31Mar 29Mar 26Mar 22Mar 18Mar 15Mar 11
16°FMar 30Mar 26Mar 22Mar 19Mar 17Mar 14Mar 11Mar 8Mar 2

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 23Sep 27Sep 30Oct 2Oct 5Oct 7Oct 10Oct 13Oct 18
32°FOct 2Oct 7Oct 11Oct 14Oct 17Oct 20Oct 23Oct 26Oct 31
28°FOct 15Oct 21Oct 25Oct 29Oct 31Nov 2Nov 5Nov 9Nov 13
24°FOct 29Nov 2Nov 5Nov 9Nov 11Nov 14Nov 17Nov 21Nov 26
20°FNov 8Nov 13Nov 16Nov 20Nov 23Nov 26Nov 29Dec 2Dec 9
16°FNov 18Nov 23Nov 27Dec 1Dec 3Dec 6Dec 11Dec 16Dec 23

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°F170163157153149146141137130
32°F193186181176172167163158151
28°F217210205201197193188182173
24°F242234228225221217213209202
20°F267257252247242238234229223
16°F285277271267262257252247239

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
6,781
Cooling degree days, base 65°F
631
Growing degree days, base 40°F
4,716
Growing degree days, base 45°F
3,637
Growing degree days, base 50°F
2,693
Growing degree days, base 55°F
1,872
Growing degree days, base 60°F
1,180

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,30300
February1,13200
March962113
April574261
May25341275
June47140543
July9216673
August19165611
September13660379
October4477121
November780017
December1,11901

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 24.3 km from Merrill. 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 USW00014845 (Saginaw Mbs Intl AP). Public domain.