St Ignace, MI Frost Dates & Growing Season

The two dates every St Ignace garden is planned around, plus ready-computed planting windows for the most popular crops.

Last spring frost
May 16
~50% chance of frost after
First fall frost
Oct 13
~50% chance of frost before
Growing season
150 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 30 May 16 May 29
First fall frost Oct 30 Oct 13 Sep 30
Hard freeze (28°F), median last May 4 · first Oct 28

Computed from NOAA 1991–2020 climate normals at the ST IGNACE 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 St Ignace

Computed from St Ignace'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 21 – Apr 4 May 23 – May 30
🫑 Peppers Mar 7 – Mar 21 May 30 – Jun 6
🥬 Lettuce Apr 4 – Apr 18 Apr 18 – May 2 Apr 18 – May 16
🫛 Peas Apr 4 – Apr 18
🥕 Carrots Apr 25 – May 16
🥦 Broccoli Mar 28 – Apr 11 Apr 25 – May 9
🥬 Kale Apr 4 – Apr 18 Apr 18 – May 2 Apr 18 – May 2
🥒 Cucumbers Apr 18 – Apr 25 May 23 – May 30 May 23 – May 30
🥒 Zucchini Apr 18 – Apr 25 May 23 – May 30 May 23 – May 30
🫘 Green Beans (Bush) May 23 – May 30
🌽 Sweet Corn May 23 – May 30
🌿 Basil Apr 4 – Apr 18 May 23 – May 30 May 30 – Jun 6
🧄 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 St Ignace's dates automatically after a lookup.

Reading the season in St Ignace

Roughly 150 frost-free days gives St Ignace gardeners room for nearly every common vegetable. Warm-season crops go out after May 16; a fall garden sown in late summer matures comfortably before the Oct 13 frost.

Frequently asked questions

When is the last frost in St Ignace, MI?

The average last spring frost in St Ignace is around May 16, 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 St Ignace, MI?

The average first fall frost in St Ignace 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 St Ignace?

About 150 frost-free days on average, from May 16 to Oct 13. That fits nearly all common vegetables, though the longest-season melons and sweet potatoes benefit from transplants.

What USDA zone is St Ignace 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.