Crawford County climate

Crawford County Frost Dates and Growing Season

NOAA 1991-2020 normals for Grayling, 7.8 km from Crawford County, elevation 1137 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Grayling. 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 23 and the first fall freeze around September 27, a growing season of about 124 days.

Median at 36°F
last June 4, first September 14
Median at 32°F
last May 23, first September 27
Median at 28°F
last May 10, first October 9

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 24Jun 16Jun 11Jun 7Jun 4Jun 2May 30May 26May 21
32°FJun 7Jun 1May 30May 26May 23May 21May 17May 13May 6
28°FMay 26May 21May 17May 13May 10May 7May 3Apr 30Apr 25
24°FMay 16May 9May 5May 1Apr 28Apr 25Apr 21Apr 18Apr 13
20°FMay 3Apr 27Apr 23Apr 19Apr 16Apr 13Apr 10Apr 6Apr 3
16°FApr 21Apr 16Apr 12Apr 9Apr 6Apr 3Apr 1Mar 29Mar 25

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°FAug 28Sep 2Sep 6Sep 10Sep 14Sep 17Sep 20Sep 24Sep 29
32°FSep 11Sep 16Sep 21Sep 24Sep 27Sep 30Oct 2Oct 6Oct 10
28°FSep 25Sep 30Oct 2Oct 5Oct 9Oct 12Oct 16Oct 20Oct 26
24°FOct 6Oct 14Oct 18Oct 21Oct 24Oct 27Oct 31Nov 2Nov 6
20°FOct 22Oct 28Nov 1Nov 2Nov 5Nov 8Nov 11Nov 15Nov 20
16°FNov 1Nov 5Nov 9Nov 12Nov 15Nov 18Nov 22Nov 25Dec 1

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°F1211131081039994888171
32°F146139133129124120115110104
28°F172165160155151146142137129
24°F199191186181176172167161154
20°F222215210205201197192187178
16°F242235230225220216212207200

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
8,228
Cooling degree days, base 65°F
353
Growing degree days, base 40°F
3,779
Growing degree days, base 45°F
2,830
Growing degree days, base 50°F
2,013
Growing degree days, base 55°F
1,317
Growing degree days, base 60°F
752

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,46100
February1,29600
March1,15005
April727131
May36822189
June11374415
July46128547
August6695494
September24030263
October592363
November91706
December1,25200

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 7.8 km from Crawford County. 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 USC00203391 (Grayling). Public domain.