Ann Arbor U Of Mich, MI Frost Dates & Growing Season

The two dates every Ann Arbor U Of Mich garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
May 3
~50% chance of frost after
First fall frost
Oct 13
~50% chance of frost before
Growing season
163 days
frost-free stretch
USDA zone
≈ 6a
estimated from nearby reference
Risky (1 year in 10)MedianSafe (9 years in 10)
Last spring frost Apr 20 May 3 May 20
First fall frost Oct 27 Oct 13 Sep 29
Hard freeze (28°F), median last Apr 23 · first Oct 26

Computed from NOAA 1991–2020 climate normals at the ANN ARBOR U OF MICH station. "Safe" means frost past that date happens only about one year in ten. Your exact garden can still run days either way with elevation and terrain — check your own ZIP with the frost date lookup.

Planting windows for Ann Arbor U Of Mich

Computed from Ann Arbor U Of Mich's own frost dates. Click any crop for the full zone-6 growing guide — varieties, spacing, fall plantings, and more.

CropStart seeds indoorsTransplantDirect sow
🍅 Tomatoes Mar 8 – Mar 22 May 10 – May 17
🫑 Peppers Feb 22 – Mar 8 May 17 – May 24
🥬 Lettuce Mar 22 – Apr 5 Apr 5 – Apr 19 Apr 5 – May 3
🫛 Peas Mar 22 – Apr 5
🥕 Carrots Apr 12 – May 3
🥦 Broccoli Mar 15 – Mar 29 Apr 12 – Apr 26
🥬 Kale Mar 22 – Apr 5 Apr 5 – Apr 19 Apr 5 – Apr 19
🥒 Cucumbers Apr 5 – Apr 12 May 10 – May 17 May 10 – May 17
🥒 Zucchini Apr 5 – Apr 12 May 10 – May 17 May 10 – May 17
🫘 Green Beans (Bush) May 10 – May 17
🌽 Sweet Corn May 10 – May 17
🌿 Basil Mar 22 – Apr 5 May 10 – May 17 May 17 – May 24
🧄 Garlic Fall: Sep 1 – Sep 29

Want this for all 50 crops, or as a printable seed-shelf schedule? Use the planting calendar and the seed starting scheduler — both can use Ann Arbor U Of Mich's dates automatically after a lookup.

Reading the season in Ann Arbor U Of Mich

Roughly 163 frost-free days gives Ann Arbor U Of Mich gardeners room for nearly every common vegetable. Warm-season crops go out after May 3; a fall garden sown in late summer matures comfortably before the Oct 13 frost.

Frequently asked questions

When is the last frost in Ann Arbor U Of Mich, MI?

The average last spring frost in Ann Arbor U Of Mich is around May 3, based on 1991–2020 climate normals. That's a median — about half of years see a later frost, so tender crops are safest going out a week or two after this date.

When is the first frost in Ann Arbor U Of Mich, MI?

The average first fall frost in Ann Arbor U Of Mich arrives around Oct 13. Crops still in the garden need to mature before then, and frost-tender plants need harvesting or protection as the date approaches.

How long is the growing season in Ann Arbor U Of Mich?

About 163 frost-free days on average, from May 3 to Oct 13. That fits nearly all common vegetables, though the longest-season melons and sweet potatoes benefit from transplants.

What USDA zone is Ann Arbor U Of Mich in?

USDA zone 6a on the 2023 Plant Hardiness Zone Map. Note that zones describe winter cold, not frost timing — these frost dates are the numbers to plan plantings around.