Last frost date in Ann Arbor, MI
The average last frost in Ann Arbor is May 5. By May 20 the chance of another 32°F night drops to 1 in 10. The first fall frost usually arrives about October 10, which leaves 157 frost-free days. An early freeze before September 28 happens one year in ten.
- Safe after (10% risk)
- May 20
- Average first frost
- Oct 10
- Frost-free season
- 157 days
- Hard freeze (28°F) ends
- Apr 24
No frost in the next 7 nights
Later than usual: the average first frost here is October 10.
National Weather Service forecast, updated Oct 22, 12:57 UTC
- ThuOct 2243°
- FriOct 2341°
- SatOct 2442°
- SunOct 2545°
- MonOct 2644°
- TueOct 2741°
- WedOct 2841°
Planting calendar for Ann Arbor
Windows count forward or back from the average frost dates above. Click a crop for dates across Michigan.
TomatoesMay 12–May 26
PumpkinsMay 19–Jun 2
SunflowersMay 5–May 26
CucumbersMay 19–May 26
CornMay 12–May 26
Sweet potatoesMay 26–Jun 9
WatermelonMay 19–Jun 2
Green beansMay 12–Jun 2
ZucchiniMay 12–May 26
OkraMay 26–Jun 9
PeppersMay 19–Jun 2
BasilMay 12–May 26
Butternut squashMay 12–May 26
CantaloupeMay 19–Jun 2
EggplantMay 19–Jun 2
PotatoesApr 7–Apr 21
OnionsMar 24–Apr 14
CarrotsApr 14–May 19
LettuceApr 21–May 12
BroccoliApr 7–Apr 21
BeetsApr 7–May 19
PeasMar 24–Apr 7
CabbageApr 7–Apr 21
RadishesMar 31–May 12
Brussels sproutsApr 21–May 5
SpinachMar 24–Apr 14
CilantroApr 21–May 12
KaleApr 7–Apr 21
Collard greensApr 7–Apr 21
TurnipsApr 7–Apr 21
DillMay 5–May 19
CeleryMay 12–May 19
CauliflowerApr 21–May 5
LeeksApr 21–May 5
Swiss chardApr 21–May 19
ParsleyApr 21–May 12
Tulip bulbsSep 26–Oct 31
GarlicSep 19–Oct 24
Daffodil bulbsSep 12–Oct 24
StrawberriesApr 7–Apr 21
AsparagusApr 7–Apr 21Frost probabilities
| Threshold | Spring, 90% chance later | Spring, 50% | Spring, 10% | Fall, 10% chance earlier | Fall, 50% | Fall, 90% |
|---|---|---|---|---|---|---|
| Light frost, 32°F | Apr 21 | May 5 | May 20 | Sep 28 | Oct 10 | Oct 24 |
| Hard freeze, 28°F | Apr 10 | Apr 24 | May 11 | Oct 7 | Oct 23 | Nov 6 |
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 Ann Arbor SE (USC00200228) sits 3.1 miles from the center of Ann Arbor at 832 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 Ann Arbor, MI?
The average last frost date in Ann Arbor is May 5, based on NOAA 1991–2020 climate normals. There is a 10% chance of frost after May 20.
When is the first frost in Ann Arbor?
The first frost in fall usually comes around October 10. One year in ten it arrives before September 28.
How long is the growing season in Ann Arbor?
About 157 days between the average last and first frost.
When should I plant tomatoes in Ann Arbor?
Plant tomato seedlings outside from May 12 to May 26. Start seeds indoors six to eight weeks earlier.
Nearby in Michigan
- WestlandApr 20
- NoviMay 1
- RomulusApr 20
- LivoniaMay 1
- Garden CityMay 1
- InksterApr 20
- Dearborn HeightsMay 1
- Farmington HillsMay 1
- TaylorApr 20
- Allen ParkMay 1
- DearbornMay 1
- SouthgateApr 20