Mason County climate

Mason County Frost Dates and Growing Season

NOAA 1991-2020 normals for Ludington 4 Se, 5.9 km from Mason County, elevation 690 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Ludington 4 Se. 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 17 and the first fall freeze around October 7, a growing season of about 144 days.

Median at 36°F
last May 30, first September 26
Median at 32°F
last May 17, first October 7
Median at 28°F
last May 1, first October 21

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 13Jun 7Jun 4Jun 1May 30May 26May 23May 19May 12
32°FJun 1May 27May 23May 20May 17May 12May 7May 2Apr 28
28°FMay 21May 15May 9May 4May 1Apr 29Apr 26Apr 22Apr 16
24°FMay 7Apr 30Apr 27Apr 23Apr 19Apr 16Apr 12Apr 7Apr 1
20°FApr 22Apr 17Apr 12Apr 8Apr 5Apr 2Mar 31Mar 27Mar 20
16°FApr 11Apr 4Apr 1Mar 29Mar 26Mar 22Mar 19Mar 14Mar 8

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 9Sep 15Sep 19Sep 23Sep 26Sep 30Oct 3Oct 7Oct 12
32°FSep 20Sep 26Oct 1Oct 4Oct 7Oct 11Oct 15Oct 19Oct 25
28°FOct 2Oct 7Oct 12Oct 16Oct 21Oct 25Oct 30Nov 1Nov 6
24°FOct 16Oct 25Oct 30Nov 2Nov 4Nov 7Nov 10Nov 15Nov 20
20°FNov 3Nov 6Nov 10Nov 14Nov 18Nov 22Nov 27Dec 1Dec 7
16°FNov 13Nov 20Nov 24Nov 29Dec 2Dec 5Dec 9Dec 15Dec 22

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°F14313412812412011511110597
32°F168161154148144139133127120
28°F194187181176171166160154144
24°F224215209203199195189183174
20°F251243237232228223218212205
16°F277268262257252246242237228

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
7,239
Cooling degree days, base 65°F
363
Growing degree days, base 40°F
4,071
Growing degree days, base 45°F
3,052
Growing degree days, base 50°F
2,166
Growing degree days, base 55°F
1,414
Growing degree days, base 60°F
803

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,30000
February1,12100
March1,00408
April641143
May32816198
June10269419
July30131566
August40104529
September18039318
October517481
November82206
December1,15301

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 5.9 km from Mason County. Low ground, valleys and open fields freeze earlier and later than a town center or a hillside.

More

Sources

NOAA NCEI U.S. Climate Normals, 1991-2020, annual and seasonal normals for station USC00204954 (Ludington 4 Se). Public domain.