FrostList

When to Winterize Your RV in Glendale, AZ

ON TRACK171 days until first 28°F freezeDec 29

Glendale's deadline to winterize your RV is December 19: the local first 28°F freeze runs December 29 on average and December 10 at its earliest (1991–2020 normals). The early-to-late range spans roughly 43 days, so treat the median as a midpoint, not a promise.

OUTLOOK

Typical first first 28°F freeze near Dec 29; local deadline about Dec 19. The live 10-day outlook loads here.

Local freeze dates for Glendale

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Nov 28Dec 15Jan 7
28°F (hard freeze)Dec 10Dec 29Jan 22

NOAA station: Youngtown · 7.7 mi away · 1,135 ft elevation.

For Glendale, the nearest NOAA station with freeze data is Youngtown, 7.7 miles out at 1,135 feet. Median first-freeze dates there run 32°F by Dec 15, 28°F by Dec 29. The 28°F freeze has come as early as Dec 10 and as late as Jan 22, a 43-day spread. Spring's last 32°F freeze clears around Jan 20.

Glendale usually sees its first 32°F night about Dec 15, with the first 28°F hard freeze close behind near Dec 29. The 32°F date swings from Nov 28 at its earliest to Jan 7 at its latest, near 40 days. The last spring freeze averages Jan 20 and as late as Feb 18, which sets the safe window for reopening outdoor water and de-winterizing gear. Snow barely registers here; the freeze date, around Jan 20, 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

Glendale freezes close to Peoria (Dec 29) and later than Avondale (Jan 4) — a reminder that even nearby towns differ by days. Statewide, Arizona prep dates run Sep 29 through Dec 25, which is why Glendale gets its own number rather than a Arizona-wide average. The same freeze also decides when to shut down your sprinklers and winterize a boat.

Other winter jobs in Glendale

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

Sprinklers → Dec 19Frozen pipes → Nov 28Car battery → Dec 29Sump pump → Jan 20Boat → Dec 22Motorcycle → Dec 15

See the full Glendale 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 Glendale?
Wait until the last spring freeze has passed, which averages near Jan 20 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 Youngtown, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.