FrostList

When to Winterize Your RV in Surprise, AZ

ON TRACK171 days until first 28°F freezeDec 29

In a typical year, winterize your RV in Surprise by December 19. The median first 28°F hard freeze at Surprise's NOAA station is December 29 (1991–2020 normals); one year in ten it arrives as early as December 10. Cold deepens quickly here — only about 14 days separate the first frost from that hard freeze.

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 Surprise

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 · 4.5 mi away · 1,135 ft elevation.

The reference station for Surprise is Youngtown (4.5 mi, 1,135 ft). First freeze there: 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.

The freeze arrives in two steps in Surprise: 32°F around Dec 15, then a hard 28°F near Dec 29. That first freezing night has ranged from Nov 28 to Jan 7, roughly a 40-day spread. On the spring side, the last 32°F freeze clears around Jan 20 and as late as Feb 18 — the green light for reopening water and de-winterizing. With almost no snow in a normal year, cold — not plowing — sets the calendar, and it centers on Jan 20.

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

Compared with nearby cities, Surprise's first-freeze date near Dec 29 sits close to Peoria (Dec 29) and close to Glendale (Dec 29). Arizona's deadlines span Sep 29 to Dec 25 statewide — one date for all of Arizona would be off by weeks for Surprise. Once you know Surprise's freeze date, use it to shut down your sprinklers and winterize a boat too.

Other winter jobs in Surprise

Every task below is dated to Surprise'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 Surprise 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 Surprise?
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.