Mayville climate

Mayville Frost Dates and Growing Season

NOAA 1991-2020 normals for Westfield 2 Sse, 8.2 km from Mayville, elevation 707 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Westfield 2 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 April 21 and the first fall freeze around November 5, a growing season of about 197 days.

Median at 36°F
last May 1, first October 26
Median at 32°F
last April 21, first November 5
Median at 28°F
last April 9, first November 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 16May 11May 7May 4May 1Apr 29Apr 26Apr 24Apr 20
32°FMay 5May 1Apr 27Apr 24Apr 21Apr 19Apr 16Apr 13Apr 8
28°FApr 23Apr 19Apr 16Apr 12Apr 9Apr 6Apr 3Apr 1Mar 28
24°FApr 12Apr 6Apr 3Apr 2Mar 31Mar 29Mar 25Mar 20Mar 15
20°FApr 3Mar 31Mar 28Mar 24Mar 21Mar 18Mar 15Mar 12Mar 8
16°FMar 27Mar 22Mar 18Mar 16Mar 14Mar 11Mar 8Mar 4Feb 27

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°FOct 11Oct 17Oct 21Oct 24Oct 26Oct 30Nov 1Nov 4Nov 8
32°FOct 23Oct 28Nov 1Nov 3Nov 5Nov 7Nov 11Nov 14Nov 19
28°FNov 1Nov 5Nov 8Nov 11Nov 14Nov 17Nov 20Nov 25Dec 1
24°FNov 10Nov 14Nov 18Nov 21Nov 25Nov 28Dec 1Dec 6Dec 12
20°FNov 17Nov 23Nov 27Dec 1Dec 4Dec 8Dec 12Dec 16Dec 23
16°FNov 25Dec 1Dec 6Dec 11Dec 15Dec 19Dec 24Dec 30Jan 5

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°F196190185181177173169163154
32°F216209205201197193189184176
28°F239230225221217213209205199
24°F260253248243239234230225218
20°F281272266261258253249244236
16°F298291286281276272267260254

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
5,998
Cooling degree days, base 65°F
785
Growing degree days, base 40°F
5,230
Growing degree days, base 45°F
4,071
Growing degree days, base 50°F
3,049
Growing degree days, base 55°F
2,162
Growing degree days, base 60°F
1,399

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,17302
February1,02902
March905017
April526791
May22249312
June42161570
July4263724
August7206663
September8588454
October35612179
November674033
December97504

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 8.2 km from Mayville. 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 USC00309189 (Westfield 2 Sse). Public domain.