Mackinac Island, Michigan, sits in USDA hardiness zone 6a — a range where zone-matched perennials and frost-aware annual timing set what succeeds.
A short list that earns its place here — cabbage, blackberry, california poppy, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Even in Mackinac Island, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Mackinac Island lot. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around Mackinac Island — soil, climate, flood, and parcel records. How we handle your address.
No card required · your full report in seconds
Mackinac Island — the short answer
Mackinac Island, Michigan: USDA zone 6a, about 151 days between hard freezes, across 3K acres of city.
- USDA zone
- 6a
- USDA PHZM 2023
- Last hard freeze (28°F)
- May 13
- Mackinac County normal — NOAA 1991–2020, nearest to this town
- First hard freeze (28°F)
- Oct 11
- Mackinac County normal — NOAA 1991–2020, nearest to this town
- Days between freezes
- ~151
- Mackinac County normal — NOAA 1991–2020, nearest to this town
- City area
- 3K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. No 30-year normal resolves at this town’s own centroid, so the hard-freeze dates are Mackinac County’s — the closest measured record, labelled as such rather than passed off as local.
Hardiness Zone Range
Zone 6a is Mackinac Island's average, not your lot's — a low corner or a tree line moves it. Against Mackinac Island's 151-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Mackinac Island
Each reading below is measured for Mackinac Island itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
From county recordsMackinac Island runs about 151 days between hard freezes (read from Mackinac County, the closest normal to Mackinac Island) — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredMackinac Island sits in USDA hardiness zone 6a.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country Mackinac Island is in
Mackinac Island sits in the Northern Lakes and Forests — EPA Level III, inside the wider Northern Forests. That is read at Mackinac Island's own centroid rather than borrowed from Mackinac County.
What Grows in Mackinac Island
Every plant below cleared Mackinac Island's own zone 6a and its 151-day season. Each card opens that plant's Michigan profile. How we score.
Is it too late to plant in Mackinac Island?
For most of the year, no — what changes is which crops still fit the days remaining. Cool-season crops can go in from around Apr 15; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near May 13 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 11 — long-season crops need about 90 days of runway, quick greens only 30. Even past midsummer there is room for a true fall garden here, and garlic planted near the close carries the momentum into next year.
What's on the federal record near Mackinac Island
Closest first, within ~10 miles of Mackinac Island. Listing isn't leaking, and distance isn't exposure.
- Mackinac Island Wastewater PlantUnderground Storage Tanks · 1300 ft
- Mackinac Island State ParkUnderground Storage Tanks · 1300 ft
- Astor Street BuildingUnderground Storage Tanks · 0.8 mi
- Union Terminal Piers IncUnderground Storage Tanks · 0.8 mi
- Biddle Point Pumping StationUnderground Storage Tanks · 1.0 mi
- Beaver DockUnderground Storage Tanks · 1.1 mi
- Water Filtration PlantUnderground Storage Tanks · 1.1 mi
- US DEPT/HOMELAND SECURITYBrownfields · 3.8 mi
- ACE COATINGS UNLIMITED INCBrownfields · 3.8 mi
- Mdot St. Ignace Maintenance GarageUnderground Storage Tanks · 3.9 mi
- CLOVERLAND ELECTRIC COOPERATIVEBrownfields · 3.9 mi
- MICHIGAN DEPT TRANSPORTATION ST IGNACE GARAGEBrownfields · 3.9 mi
6 more sites are on the record inside the same radius. See them on the map
Measured from Mackinac Island's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near Mackinac Island.
Total Sites
97
within ~10 miles of Mackinac Island
Risk Level
Moderate
Highest-severity
27 brownfield sites
Sources Checked
within ~10 miles of Mackinac Island
Severity Distribution
within ~10 miles of Mackinac Island
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Mackinac Island, Underground Storage Tanks runs higher than the national average — 63 sites within ~10 miles of Mackinac Island. It's not cause for alarm — it's worth knowing, and there's a sensible way to grow around it.
Underground Storage Tanks: Underground storage tanks are the single most common source of soil contamination near homes and gardens.
Use raised beds with imported soil — this eliminates the primary soil-contact pathway.
Check your specific parcel in Mackinac Island
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the Mackinac Island average
Your land is one point inside Mackinac Island
Everything above resolves to Mackinac Island as a whole — one PHZM band, read across 3K acres, with hard-freeze dates borrowed from Mackinac County’s record because no 30-year normal resolves at this city’s own centroid. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at city scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better local average.
Your Lot vs the Mackinac Island Average
Mackinac Island Average
- ●USDA Zones 6a, averaged across Mackinac Island
- ●One soil character for all of Mackinac Island
- ●Frost dates read at Mackinac Island's scale: May 13 to Oct 11
YOUR Parcel
- ✓Your exact zone, not Mackinac Island's 6a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Mackinac Island
Pull a site-specific report for your exact address in Mackinac Island, Michigan — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Mackinac Island averages can't show:
We read public map data around Mackinac Island — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Mackinac Island average
How we know this about Mackinac Island
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Mackinac County’s record, because none resolves here; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at city grain anywhere on this page — there is no city-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Mackinac Island
When does frost risk typically end in Mackinac Island?
The last hard freeze (28°F) in Mackinac Island typically lands around May 13, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about Jun 3.
When is the first frost in Mackinac Island?
The first hard freeze (28°F) in Mackinac Island typically arrives around Oct 11, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Sep 27, so the watching starts about Sep 11 — about 151 days after the spring freeze cleared.
How long is the growing season in Mackinac Island?
Measured between 28°F hard freezes, Mackinac Island sees about 151 frost-free days — roughly May 13 through Oct 11, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer Jun 3 to Sep 27, about 116 days.
Is the soil safe to grow vegetables in Mackinac Island?
The federal record around Mackinac Island shows 97 documented sites, mostly Underground Storage Tanks entries (63), the nearest Underground Storage Tanks record about 0.2 miles out — a typical footprint for a growing area, and proximity to a documented site is information, not a diagnosis of any one yard. It's worth seeing which recorded sites sit closest to where you grow, and testing the soil before new food beds near any of them.
How do I protect my plants from frost in Mackinac Island?
From about Sep 11 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 11 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 11. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Mackinac Island's scale — its 6a band and its 151-day season. Your yard writes its own version of Mackinac Island's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Mackinac Island’s own scale
5 of the readings below were taken at Mackinac Island's own scale — the 2,786 acres it covers and 97 documented sites around it; 5 are borrowed from a wider read, named and linked below.
Measured here
- Mackinac Island's own USDA hardiness band, zones 6aUSDA PHZM 2023
- 97 documented contamination sites on the federal record near Mackinac Island, the closest Underground Storage Tanks record about 0.2 miles out from the town centreFederal environmental registers
- Mackinac Island's boundary and the 2,786 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 6a and a ~151-day seasonGrowable Ground crop-matching engine
- The ecoregion at Mackinac Island's own centroid, the Northern Lakes and ForestsUS EPA Level III Ecoregions
Inherited from a wider read
- The 28°F hard-freeze dates — Mackinac Island has no normal of its own, so its county's is the closest measured readfrom Mackinac County
- Soil character — no town-scale survey exists, so Mackinac Island's 2,786 acres read through its county's SSURGO summaryfrom Mackinac County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Mackinac County
- The growing challenges every Michigan grower plans around — written at state scale, so they stay on the state guidefrom Michigan
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Mackinac County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Mackinac Island's 2,786 acreswhy one lot differs from the next →
- Which side of Mackinac Island you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 2,786 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Underground Storage Tanks record about 0.2 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Mackinac Island-wide figureread your own land →
More in Michigan
Growing region
Nearby growing guides