Last frost date in Royal Oak, MI

Average last frost
April 21

Expect the last frost in Royal Oak around April 21. Frost after May 6 happens in only one year out of ten. The first fall frost usually arrives about October 31, which leaves 190 frost-free days. An early freeze before October 17 happens one year in ten.

Safe after (10% risk)
May 6
Average first frost
Oct 31
Frost-free season
190 days
Hard freeze (28°F) ends
Apr 8
Next 7 nights in Royal Oak

No frost in the next 7 nights

National Weather Service forecast, updated Oct 22, 12:57 UTC

  1. ThuOct 2245°
  2. FriOct 2342°
  3. SatOct 2444°
  4. SunOct 2548°
  5. MonOct 2645°
  6. TueOct 2742°
  7. WedOct 2843°
JanFebMarAprMayJunJulAugSepOctNovDecLast frost Apr 21First frost Oct 31190 frost-free daysBlue: chance of 32°F frost. Green: average frost-free season.JFMAMJJASOND190 frost-free days
Frost risk through the year at Detroit City Airport, 10.0 miles from Royal Oak.

Planting calendar for Royal Oak

Windows count forward or back from the average frost dates above. Click a crop for dates across Michigan.

Start indoorsPlant outSow outdoorsFall plantingAverage last and first frost
Warm-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
TomatoesApr 28–May 12
PumpkinsMay 5–May 19
SunflowersApr 21–May 12
CucumbersMay 5–May 12
CornApr 28–May 12
Sweet potatoesMay 12–May 26
WatermelonMay 5–May 19
Green beansApr 28–May 19
ZucchiniApr 28–May 12
OkraMay 12–May 26
PeppersMay 5–May 19
BasilApr 28–May 12
Butternut squashApr 28–May 12
CantaloupeMay 5–May 19
EggplantMay 5–May 19
Cool-season crops
JanFebMarAprMayJunJulAugSepOctNovDec
PotatoesMar 24–Apr 7
OnionsMar 10–Mar 31
CarrotsMar 31–May 5
LettuceApr 7–Apr 28
BroccoliMar 24–Apr 7
BeetsMar 24–May 5
PeasMar 10–Mar 24
CabbageMar 24–Apr 7
RadishesMar 17–Apr 28
Brussels sproutsApr 7–Apr 21
SpinachMar 10–Mar 31
CilantroApr 7–Apr 28
KaleMar 24–Apr 7
Collard greensMar 24–Apr 7
TurnipsMar 24–Apr 7
DillApr 21–May 5
CeleryApr 28–May 5
CauliflowerApr 7–Apr 21
LeeksApr 7–Apr 21
Swiss chardApr 7–May 5
ParsleyApr 7–Apr 28
Fall bulbs and garlic
JanFebMarAprMayJunJulAugSepOctNovDec
Tulip bulbsOct 17–Nov 21
GarlicOct 10–Nov 14
Daffodil bulbsOct 3–Nov 14
Perennials
JanFebMarAprMayJunJulAugSepOctNovDec
StrawberriesMar 24–Apr 7
AsparagusMar 24–Apr 7

Frost probabilities

ThresholdSpring, 90% chance laterSpring, 50%Spring, 10%Fall, 10% chance earlierFall, 50%Fall, 90%
Light frost, 32°FApr 7Apr 21May 6Oct 17Oct 31Nov 11
Hard freeze, 28°FMar 27Apr 8Apr 22Oct 29Nov 9Nov 23

Read the spring 10% column as the date after which only one year in ten still gets frost. That is the safer date for tomatoes, peppers and basil.

Where these numbers come from

NOAA station Detroit City Airport (USW00014822) sits 10.0 miles from the center of Royal Oak at 626 feet. Its averages cover 1991 to 2020. Low spots, valleys and open fields can keep getting frost a week or two after the station stops; city centers and lakeshores usually get less of it.

Questions

When is the last frost in Royal Oak, MI?

The average last frost date in Royal Oak is April 21, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 6.

When is the first frost in Royal Oak?

The first frost in fall usually comes around October 31. One year in ten it arrives before October 17.

How long is the growing season in Royal Oak?

About 190 days between the average last and first frost.

When should I plant tomatoes in Royal Oak?

Plant tomato seedlings outside from April 28 to May 12. Start seeds indoors six to eight weeks earlier.

Nearby in Michigan

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