FrostList

When to Winterize Your RV in Duluth, MN

ON TRACK106 days until first 28°F freezeOct 25

Aim to winterize your RV in Duluth by October 15, roughly a week and a half before the median first 28°F freeze of October 25, which one fall in ten shows up by October 9. The early-odds date runs roughly 16 days ahead of the median, so build in that buffer.

OUTLOOK

Typical first first 28°F freeze near Oct 25; local deadline about Oct 15. The live 10-day outlook loads here.

Local freeze dates for Duluth

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Sep 25Oct 12Oct 26
28°F (hard freeze)Oct 9Oct 25Nov 7
24°F (severe)Oct 21Nov 3Nov 16

NOAA station: Duluth Harbor Stn · 1.4 mi away · 610 ft elevation.

The reference station for Duluth is Duluth Harbor Stn (1.4 mi, 610 ft). First freeze there: 32°F by Oct 12, 28°F by Oct 25, 24°F by Nov 3. Year to year the 28°F date has ranged from Oct 9 to Nov 7 — about 29 days apart. Spring's last 32°F freeze clears around May 14. Snowfall averages 56 inches a year, first reaching an inch near November.

The freeze arrives in two steps in Duluth: 32°F around Oct 12, then a hard 28°F near Oct 25. The 32°F date swings from Sep 25 at its earliest to Oct 26 at its latest, near 31 days. The last spring freeze averages May 14 and as late as Jun 1, which sets the safe window for reopening outdoor water and de-winterizing gear. Roughly 56 inches of snow fall in an average year, so a clear roof edge and a running snow blower matter as much as the freeze itself.

Your rv checklist

  1. Drain the fresh, gray, and black tanks, then drain the water heater only after it has cooled and lost pressure.
  2. Bypass the water heater so you do not waste six gallons of antifreeze filling the tank.
  3. Blow out the lines with a compressor at about 30–40 psi, then pump non-toxic RV antifreeze through every faucet until it runs pink.
    Helpful gear: RV antifreeze (6-pack) — Recommended pick
  4. Use a water-pump converter kit to draw antifreeze straight from the jug through the plumbing.
    Helpful gear: Water pump converter kit — Recommended pick
  5. Pour a cup of antifreeze into each drain trap and the toilet to protect the seals.
  6. Fit a blow-out plug at the city-water inlet so you can clear that line too.
    Helpful gear: Blow-out plug — Recommended pick
  7. Remove batteries or put them on a maintainer, and store them off a cold concrete floor.
  8. Cover roof vents, close the propane, and set out traps or deterrents so mice do not move in.

What to have on hand

RV antifreeze (6-pack)
Non-toxic pink fluid for the fresh-water plumbing and traps.
Recommended pick
Water pump converter kit
Siphon kit that draws antifreeze straight through the pump.
Recommended pick
Blow-out plug
Adapter that lets a compressor clear the lines before antifreeze.
Recommended pick
Heated fresh-water hose
For anyone staying hooked up through a cold snap.
Recommended pick

What this means locally

Duluth freezes later than Blaine (Oct 13) and later than Coon Rapids (Oct 13) — a reminder that even nearby towns differ by days. Statewide, Minnesota prep dates run Sep 28 through Oct 19, which is why Duluth gets its own number rather than a Minnesota-wide average. The same freeze also decides when to shut down your sprinklers and winterize a boat.

Other winter jobs in Duluth

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

Sprinklers → Oct 15Frozen pipes → Sep 25Ice dams → Oct 16Car battery → Oct 25Snow blower → Oct 25Sump pump → May 14Boat → Oct 18Motorcycle → Oct 12

See the full Duluth winter checklist, in order →

Frequently asked questions

At what temperature do RV pipes freeze?
An RV's exposed plumbing and thin-walled tanks can begin to freeze once temperatures sit in the mid-20s for a few hours, sooner than a house because there is little insulation around the lines. That is why the winterizing deadline tracks the first 28°F freeze rather than the first light frost.
How much RV antifreeze do I need?
Most travel trailers and motorhomes take about two to three gallons of non-toxic RV antifreeze, and larger rigs more. Bypassing the water heater saves roughly six gallons you would otherwise waste filling the tank. Buy an extra jug; stores sell out once the first freeze warnings hit.
Can I just use my RV furnace instead of winterizing?
Relying on the furnace is risky. A propane run-out, a tripped breaker, or a dead battery during a cold night leaves the plumbing unprotected, and the furnace may not keep the underbelly and bays warm enough anyway. Draining and adding antifreeze is the dependable way to protect the system.
How do I winterize an RV water heater?
Let the tank cool and lose pressure, then drain it and, if fitted, pull the anode rod. Do not add antifreeze to the water heater tank; instead, set the bypass valves so antifreeze skips the tank and fills only the lines. Fresh antifreeze in an unbypassed heater just wastes several gallons.
When is it safe to de-winterize an RV in Duluth?
Wait until the last spring freeze has passed, which averages near May 14 here. De-winterize by flushing the antifreeze from the lines, sanitizing the fresh tank, and checking for leaks before a trip. Reopening too early risks a surprise late freeze on a charged system.
Do I need to winterize an RV stored indoors?
A reliably heated indoor space that stays above freezing protects the plumbing, so full winterizing may not be needed. But an unheated garage or barn can still drop below freezing on a cold night. If you cannot guarantee the space stays warm, winterize to be safe.

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