FrostList

When to Winterize Your RV in Marana, AZ

ON TRACK161 days until first 28°F freezeDec 19

Aim to winterize your RV in Marana by December 9, roughly a week and a half before the median first 28°F freeze of December 19, which one fall in ten shows up by November 30. The early-to-late range spans roughly 53 days, so treat the median as a midpoint, not a promise.

OUTLOOK

Typical first first 28°F freeze near Dec 19; local deadline about Dec 9. The live 10-day outlook loads here.

Local freeze dates for Marana

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Nov 18Dec 6Dec 25
28°F (hard freeze)Nov 30Dec 19Jan 22
24°F (severe)Dec 10Jan 1Feb 3

NOAA station: Tucson 17 Nw · 12.7 mi away · 2,561 ft elevation.

Numbers for Marana come from Tucson 17 Nw, 12.7 miles away at 2,561 feet, where the medians fall 32°F by Dec 6, 28°F by Dec 19, 24°F by Jan 1. The 28°F freeze has come as early as Nov 30 and as late as Jan 22, a 53-day spread. Spring's last 32°F freeze clears around Feb 23.

Marana usually sees its first 32°F night about Dec 6, with the first 28°F hard freeze close behind near Dec 19. The 32°F date swings from Nov 18 at its earliest to Dec 25 at its latest, near 37 days. The last spring freeze averages Feb 23 and as late as Mar 22, which sets the safe window for reopening outdoor water and de-winterizing gear. Snow barely registers here; the freeze date, around Feb 23, is the one that matters.

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

Against its neighbors, Marana (first freeze Dec 19) runs later than Oro Valley (Nov 21) and about a week ahead of Tucson (Dec 30). Across Arizona, local prep deadlines in our data range from Sep 29 to Dec 25, so a statewide rule of thumb would miss Marana by weeks. In Marana, that same cold is your cue to shut down your sprinklers and winterize a boat.

Other winter jobs in Marana

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

Sprinklers → Dec 9Frozen pipes → Nov 18Car battery → Dec 19Sump pump → Feb 23Boat → Dec 12Motorcycle → Dec 6

See the full Marana 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 Marana?
Wait until the last spring freeze has passed, which averages near Feb 23 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 Tucson 17 Nw, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.