Oakland County climate

Oakland County Frost Dates and Growing Season

NOAA 1991-2020 normals for Pontiac Oakland CO Intl AP, 2.7 km from Oakland County, elevation 976 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Pontiac Oakland CO 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 29 and the first fall freeze around October 20, a growing season of about 172 days.

Median at 36°F
last May 9, first October 7
Median at 32°F
last April 29, first October 20
Median at 28°F
last April 18, first November 1

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 23May 19May 15May 11May 9May 6May 3Apr 30Apr 27
32°FMay 14May 9May 5May 1Apr 29Apr 27Apr 24Apr 20Apr 16
28°FMay 1Apr 27Apr 23Apr 20Apr 18Apr 15Apr 12Apr 9Apr 4
24°FApr 19Apr 16Apr 12Apr 9Apr 6Apr 3Apr 1Mar 29Mar 23
20°FApr 10Apr 5Apr 2Mar 31Mar 27Mar 24Mar 20Mar 17Mar 12
16°FMar 31Mar 27Mar 23Mar 20Mar 17Mar 15Mar 11Mar 8Mar 3

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 26Oct 1Oct 2Oct 5Oct 7Oct 10Oct 13Oct 16Oct 21
32°FOct 5Oct 10Oct 14Oct 17Oct 20Oct 23Oct 25Oct 29Nov 2
28°FOct 19Oct 24Oct 27Oct 30Nov 1Nov 3Nov 5Nov 9Nov 14
24°FNov 1Nov 4Nov 6Nov 9Nov 12Nov 15Nov 18Nov 21Nov 28
20°FNov 8Nov 12Nov 16Nov 20Nov 23Nov 26Nov 30Dec 3Dec 10
16°FNov 17Nov 22Nov 28Dec 1Dec 4Dec 7Dec 11Dec 16Dec 21

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°F170163159155151147143138131
32°F192185180176172169165160153
28°F215209205201197193189184177
24°F241234228224220216212207201
20°F264256251246242237233227220
16°F285277272266261257252247239

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
6,679
Cooling degree days, base 65°F
658
Growing degree days, base 40°F
4,810
Growing degree days, base 45°F
3,715
Growing degree days, base 50°F
2,754
Growing degree days, base 55°F
1,922
Growing degree days, base 60°F
1,217

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,28800
February1,10601
March946014
April556269
May24535278
June46136540
July8229687
August13187639
September12662390
October4456120
November780016
December1,12102

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 2.7 km from Oakland 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 USW00094817 (Pontiac Oakland CO Intl AP). Public domain.