Frost dates for 48104 — Ann Arbor, MI
Last spring frostMay 5median date
First fall frostOct 10median date
Growing season158 daysfrost-free
Hardiness zone6aZone 6a
How Ann Arbor compares
- In 8 years out of 10, the last spring frost in Ann Arbor falls between April 21 and May 20, a 29-day window. The first fall frost falls between September 28 and October 24.
- The median last frost is the same as the Michigan median of May 5.
- Its 158-day growing season is longer than 42% of the 878 Michigan places with a regular frost season (state median 162 days).
- The last frost is 6 days later than the zone 6a median of Apr 29. Hardiness zones measure winter cold, not season length, so use these dates rather than a zone 6a chart.
- The weather station records an average of 147 nights a year at or below 32°F.
- Compared with Detroit, MI, 52 km away, the last frost here is 8 days later than there and the growing season is 23 days shorter.
Frost probability
| Chance of frost after | Date |
|---|---|
| 90% (early) | April 21 |
| 50% (median) | May 5 |
| 10% (safe for tender plants) | May 20 |
| Chance of frost before | Date |
|---|---|
| 10% (early) | September 28 |
| 50% (median) | October 10 |
| 90% (late) | October 24 |
Frost here means 32°F (0°C). A median date means half of years have their last frost earlier and half later.
Planting calendar for Ann Arbor, MI
Frost dates for 48104 — Ann Arbor, MI — last frost May 5, first frost Oct 10, zone 6a. whenisthelastfrost.com
Crop
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Start indoors: Feb 10 to Feb 24Transplant outside: Apr 7 to Apr 21
Start indoors: Feb 24 to Mar 10Transplant outside: May 19 to Jun 2
Start indoors: Feb 24 to Mar 10Transplant outside: May 19 to Jun 2
Start indoors: Mar 10 to Mar 24Transplant outside: May 12 to May 26
Start indoors: Mar 10 to Mar 24Transplant outside: Apr 14 to Apr 28Sow outdoors: Apr 7 to May 12Plant for fall: Aug 15 to Sep 12
Start indoors: Mar 10 to Mar 24Transplant outside: Apr 7 to Apr 21Sow outdoors: Apr 7 to Apr 21Plant for fall: Aug 1 to Aug 22
Start indoors: Mar 10 to Mar 24Transplant outside: Apr 21 to May 5Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 10 to Mar 24Transplant outside: Apr 14 to Apr 28Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 10 to Mar 24Transplant outside: Apr 21 to May 5Plant for fall: Jul 4 to Jul 25
Start indoors: Mar 24 to Apr 7Transplant outside: May 26 to Jun 9Sow outdoors: May 26 to Jun 9
Start indoors: Mar 24 to Apr 7Transplant outside: May 12 to May 26
Sow outdoors: Mar 24 to Apr 14Plant for fall: Jul 18 to Aug 8
Sow outdoors: Mar 24 to Apr 14Plant for fall: Aug 15 to Sep 5
Sow outdoors: Mar 31 to May 12Plant for fall: Aug 29 to Sep 19
Start indoors: Apr 7 to Apr 14Transplant outside: May 19 to May 26Sow outdoors: May 12 to May 26Plant for fall: Jul 25 to Aug 8
Start indoors: Apr 7 to Apr 14Sow outdoors: May 12 to May 26Plant for fall: Aug 1 to Aug 15
Start indoors: Apr 7 to Apr 14Sow outdoors: May 12 to May 26
Start indoors: Apr 7 to Apr 14Transplant outside: May 19 to Jun 2
Sow outdoors: Apr 14 to May 12Plant for fall: Jul 18 to Aug 1
Sow outdoors: Apr 14 to May 12Plant for fall: Aug 1 to Aug 15
Sow outdoors: Apr 14 to May 5
Sow outdoors: Apr 21 to May 19Plant for fall: Aug 1 to Aug 15
Sow outdoors: Apr 21 to May 12Plant for fall: Aug 15 to Sep 5
Sow outdoors: May 12 to Jun 2Plant for fall: Jul 25 to Aug 8
Sow outdoors: May 12 to May 26
Transplant outside: May 19 to Jun 9
Plant for fall: Sep 26 to Oct 31
Start indoorsTransplant outsideSow outdoorsPlant for fallMedian frost dates
When to plant vegetables in Ann Arbor, MI
| Crop | Start indoors | Transplant | Sow outdoors | Fall crop |
|---|---|---|---|---|
| Onions | Feb 10 – Feb 24 | Apr 7 – Apr 21 | — | — |
| Peppers | Feb 24 – Mar 10 | May 19 – Jun 2 | — | — |
| Eggplant | Feb 24 – Mar 10 | May 19 – Jun 2 | — | — |
| Tomatoes | Mar 10 – Mar 24 | May 12 – May 26 | — | — |
| Lettuce | Mar 10 – Mar 24 | Apr 14 – Apr 28 | Apr 7 – May 12 | Aug 15 – Sep 12 |
| Kale | Mar 10 – Mar 24 | Apr 7 – Apr 21 | Apr 7 – Apr 21 | Aug 1 – Aug 22 |
| Broccoli | Mar 10 – Mar 24 | Apr 21 – May 5 | — | Jul 4 – Jul 25 |
| Cabbage | Mar 10 – Mar 24 | Apr 14 – Apr 28 | — | Jul 4 – Jul 25 |
| Cauliflower | Mar 10 – Mar 24 | Apr 21 – May 5 | — | Jul 4 – Jul 25 |
| Okra | Mar 24 – Apr 7 | May 26 – Jun 9 | May 26 – Jun 9 | — |
| Basil | Mar 24 – Apr 7 | May 12 – May 26 | — | — |
| Peas | — | — | Mar 24 – Apr 14 | Jul 18 – Aug 8 |
| Spinach | — | — | Mar 24 – Apr 14 | Aug 15 – Sep 5 |
| Radishes | — | — | Mar 31 – May 12 | Aug 29 – Sep 19 |
| Cucumbers | Apr 7 – Apr 14 | May 19 – May 26 | May 12 – May 26 | Jul 25 – Aug 8 |
| Zucchini & Summer Squash | Apr 7 – Apr 14 | — | May 12 – May 26 | Aug 1 – Aug 15 |
| Winter Squash & Pumpkins | Apr 7 – Apr 14 | — | May 12 – May 26 | — |
| Melons & Watermelon | Apr 7 – Apr 14 | May 19 – Jun 2 | — | — |
| Carrots | — | — | Apr 14 – May 12 | Jul 18 – Aug 1 |
| Beets | — | — | Apr 14 – May 12 | Aug 1 – Aug 15 |
| Potatoes | — | — | Apr 14 – May 5 | — |
| Swiss Chard | — | — | Apr 21 – May 19 | Aug 1 – Aug 15 |
| Cilantro | — | — | Apr 21 – May 12 | Aug 15 – Sep 5 |
| Green Beans | — | — | May 12 – Jun 2 | Jul 25 – Aug 8 |
| Sweet Corn | — | — | May 12 – May 26 | — |
| Sweet Potatoes | — | May 19 – Jun 9 | — | — |
| Garlic | — | — | — | Sep 26 – Oct 31 |
Dates come from the median frost dates and common extension-service timing. Adjust for your soil temperature, microclimate and the varieties you grow.
About these dates
Based on 1991–2020 NOAA climate normals for the Ann Arbor Se, MI weather station, 4 km away (elevation 833 ft (254 m)).
ZIP codes in Ann Arbor: 48103 48104 48105 48106 48107 48108 48109 48113
Frost dates near Ann Arbor
- Ypsilanti Apr 24 · Oct 24
- Saline May 2 · Oct 11
- Dexter Apr 30 · Oct 12
- Whitmore Lake May 5 · Oct 13
- Bridgewater May 2 · Oct 11
- Whittaker May 3 · Oct 10
- Salem May 3 · Oct 13
- Milan Apr 26 · Oct 19
Frequently asked questions
When is the last frost in Ann Arbor, MI?
The median last spring frost in Ann Arbor, MI is May 5. There is still about a 10% chance of frost after May 20, so wait until then to plant frost-tender crops like tomatoes and peppers.
When is the first frost in Ann Arbor, MI?
The median first fall frost is October 10, with about a 10% chance of frost before September 28.
How long is the growing season in Ann Arbor, MI?
About 158 days between the median last spring frost and first fall frost.
What planting zone is Ann Arbor, MI?
Ann Arbor, MI is in USDA hardiness zone 6a.