FrostList

When to Winterize Your Boat in Duncanville, TX

ON TRACK151 days until first 28°F freezeDec 9

Plan to haul out and winterize your boat in Duncanville by December 2. The first 28°F freeze near Duncanville averages December 9 in the 1991–2020 normals, and freeze damage often surprises owners in milder states. The early-to-late range spans roughly 47 days, so treat the median as a midpoint, not a promise.

OUTLOOK

Typical first first 28°F freeze near Dec 9; local deadline about Dec 2. The live 10-day outlook loads here.

Local freeze dates for Duncanville

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Nov 6Nov 25Dec 14
28°F (hard freeze)Nov 19Dec 9Jan 5
24°F (severe)Dec 2Dec 27Feb 1

NOAA station: Dallas Redbird AP · 3.1 mi away · 658 ft elevation.

For Duncanville, the nearest NOAA station with freeze data is Dallas Redbird AP, 3.1 miles out at 658 feet. Median first-freeze dates there run 32°F by Nov 25, 28°F by Dec 9, 24°F by Dec 27. The 28°F freeze has come as early as Nov 19 and as late as Jan 5, a 47-day spread. Spring's last 32°F freeze clears around Mar 6. Snowfall averages 1 inches a year.

Expect the first frost near Nov 25 in Duncanville and the first hard freeze by about Dec 9. The 32°F date swings from Nov 6 at its earliest to Dec 14 at its latest, near 38 days. The last spring freeze averages Mar 6 and as late as Mar 26, which sets the safe window for reopening outdoor water and de-winterizing gear. Snow barely registers here; the freeze date, around Mar 6, is the one that matters.

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

Compared with nearby cities, Duncanville's first-freeze date near Dec 9 sits later than Cedar Hill (Nov 25) and close to DeSoto (Dec 9). Texas's deadlines span Jan 1 to Dec 29 statewide — one date for all of Texas would be off by weeks for Duncanville. Once you know Duncanville's freeze date, use it to winterize an RV and store a motorcycle too.

Other winter jobs in Duncanville

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

Sprinklers → Nov 29Frozen pipes → Nov 6Car battery → Dec 9Sump pump → Mar 6RV → Nov 29Motorcycle → Nov 25

See the full Duncanville 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 Dec 9 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 TX 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 Dallas Redbird AP, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.