FrostList

When to Winterize Your Boat in Dearborn Heights, MI

ON TRACK109 days until first 28°F freezeOct 28

In Dearborn Heights, target October 21 to drain, antifreeze, and lay up the boat, about a week before the median first 28°F freeze of October 28; a surprise cold snap is exactly how freeze claims happen. The early-to-late range spans roughly 30 days, so treat the median as a midpoint, not a promise.

OUTLOOK

Typical first first 28°F freeze near Oct 28; local deadline about Oct 21. The live 10-day outlook loads here.

Local freeze dates for Dearborn Heights

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Oct 1Oct 15Oct 28
28°F (hard freeze)Oct 13Oct 28Nov 12
24°F (severe)Oct 27Nov 10Nov 27

NOAA station: Dearborn · 2.2 mi away · 605 ft elevation.

For Dearborn Heights, the nearest NOAA station with freeze data is Dearborn, 2.2 miles out at 605 feet. Median first-freeze dates there run 32°F by Oct 15, 28°F by Oct 28, 24°F by Nov 10. Year to year the 28°F date has ranged from Oct 13 to Nov 12 — about 30 days apart. Spring's last 32°F freeze clears around May 1. Snowfall averages 31 inches a year, first reaching an inch near December.

Expect the first frost near Oct 15 in Dearborn Heights and the first hard freeze by about Oct 28. The 32°F date swings from Oct 1 at its earliest to Oct 28 at its latest, near 27 days. The last spring freeze averages May 1 and as late as May 18, which sets the safe window for reopening outdoor water and de-winterizing gear. About 31 inches of snow a year is enough to justify servicing the snow blower and watching the eaves.

Your boat checklist

  1. Change the engine oil and filter while the motor is warm so contaminants leave with the old oil.
  2. Run the engine on antifreeze until pink fluid reaches the outlet, protecting the block and manifolds.
    Helpful gear: Marine antifreeze — Recommended pick
  3. Fog the cylinders with fogging oil as the engine runs down to coat internal parts against corrosion.
    Helpful gear: Fogging oil — Recommended pick
  4. Top off the fuel tank and add stabilizer to limit condensation and protect ethanol-blend fuel.
    Helpful gear: Marine fuel stabilizer — Recommended pick
  5. Drain the raw-water system, the livewell, and any washdown lines that can trap water.
  6. Remove the battery, charge it fully, and keep it on a maintainer over the layup.
    Helpful gear: Battery maintainer — Recommended pick
  7. Support the cover so snow and rain shed off, and leave vents so the interior can breathe.
  8. For an inboard or sterndrive, follow the manual closely — those blocks are the ones freeze claims hit hardest.

What to have on hand

Marine antifreeze
Propylene-glycol fluid rated for engine blocks and systems.
Recommended pick
Marine fuel stabilizer
Additive that protects ethanol-blend fuel over the layup.
Recommended pick
Fogging oil
Spray that coats cylinders against corrosion in storage.
Recommended pick
Battery maintainer
Keeps the cranking battery topped off on the trailer.
Recommended pick

What this means locally

Dearborn Heights freezes close to Livonia (Oct 28) and about a week ahead of Dearborn (Nov 6) — a reminder that even nearby towns differ by days. Statewide, Michigan prep dates run Oct 16 through Nov 2, which is why Dearborn Heights gets its own number rather than a Michigan-wide average. The same freeze also decides when to winterize an RV and store a motorcycle.

Other winter jobs in Dearborn Heights

Every task below is dated to Dearborn Heights's own freeze and snow normals.

Sprinklers → Oct 18Frozen pipes → Oct 1Ice dams → Nov 15Car battery → Oct 28Snow blower → Nov 24Sump pump → May 1RV → Oct 18Motorcycle → Oct 15

See the full Dearborn Heights winter checklist, in order →

Frequently asked questions

At what temperature does a boat engine block crack?
Trapped water in an engine block or manifold can freeze and crack the casting once temperatures fall below 32°F and stay there long enough. Inboard and sterndrive blocks hold the most water and are the most vulnerable. Draining fully and adding antifreeze before the first hard freeze near Oct 28 is the protection.
Do outboards need winterizing?
Yes. An outboard should be drained so no water sits in the powerhead or lower unit, and the fuel system stabilized. Outboards self-drain better than inboards when tilted down, but fogging the cylinders and changing the gear oil are still part of a proper layup.
Fogging oil: is it necessary?
Fogging coats the cylinder walls and internal parts with a film that resists corrosion during months of storage. On engines that sit all winter it is cheap insurance against rust, especially in humid or coastal storage. Follow your engine maker's guidance on how to apply it.
How much does boat winterization cost?
A professional winterization varies with engine type and boat size, and inboards cost more than a simple outboard. Doing it yourself costs mainly antifreeze, oil, and fogging oil. Either way, the bill is far smaller than repairing a cracked block, which is the failure winterizing prevents.
Do boats in MI really need winterizing?
If temperatures reach freezing where the boat is stored, yes. Freeze claims are common in milder states precisely because owners assume they are safe and skip the step, then a rare cold snap cracks a block. Check the local freeze dates above and protect the engine before the first hard freeze.
When should I de-winterize my boat?
De-winterize in spring once the risk of a hard freeze has passed for your area. Reconnect and charge the battery, replace drain plugs, check hoses and clamps, and inspect the fuel system before the first launch. Reopening too early leaves the block exposed to a late cold snap.

Data: NOAA 1991–2020 normals via Dearborn, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.