Inkster climate

Inkster Frost Dates and Growing Season

NOAA 1991-2020 normals for Dearborn, 6.6 km from Inkster, elevation 605 ft

Frost and the growing season

NOAA's 1991-2020 freeze probabilities for Dearborn. 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 1 and the first fall freeze around October 15, a growing season of about 166 days.

Median at 36°F
last May 12, first October 5
Median at 32°F
last May 1, first October 15
Median at 28°F
last April 20, first October 28

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 27May 23May 19May 15May 12May 9May 6May 2Apr 27
32°FMay 18May 12May 8May 4May 1Apr 29Apr 26Apr 22Apr 17
28°FMay 7Apr 30Apr 26Apr 23Apr 20Apr 16Apr 13Apr 9Apr 5
24°FApr 21Apr 16Apr 13Apr 9Apr 6Apr 4Apr 1Mar 29Mar 23
20°FApr 8Apr 4Apr 1Mar 30Mar 27Mar 23Mar 19Mar 16Mar 11
16°FMar 31Mar 27Mar 23Mar 19Mar 16Mar 13Mar 10Mar 6Feb 28

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 24Sep 28Oct 1Oct 3Oct 5Oct 8Oct 10Oct 13Oct 18
32°FOct 1Oct 6Oct 9Oct 12Oct 15Oct 18Oct 21Oct 24Oct 28
28°FOct 13Oct 18Oct 22Oct 26Oct 28Nov 1Nov 4Nov 7Nov 12
24°FOct 27Nov 1Nov 3Nov 7Nov 10Nov 13Nov 16Nov 21Nov 27
20°FNov 6Nov 11Nov 16Nov 20Nov 23Nov 27Nov 30Dec 4Dec 9
16°FNov 16Nov 23Nov 28Dec 1Dec 4Dec 7Dec 12Dec 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°F165159154150146143139135128
32°F186180175171166162158153147
28°F211204199194190186181177169
24°F237230225220215211207201194
20°F262255248244241236230226219
16°F284276271265261257252247240

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
6,366
Cooling degree days, base 65°F
736
Growing degree days, base 40°F
5,010
Growing degree days, base 45°F
3,889
Growing degree days, base 50°F
2,901
Growing degree days, base 55°F
2,047
Growing degree days, base 60°F
1,323

Growing degree days by month, base 50°F

Heating and cooling by month

MonthHeating DDCooling DDGrowing DD 50
January1,24400
February1,06401
March906116
April525379
May23339289
June43147556
July6247707
August11206660
September10684431
October4168141
November741019
December1,07102

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 6.6 km from Inkster. 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 USC00202015 (Dearborn). Public domain.