FrostList

When to Winterize Your RV in Corona, CA

ON TRACK172 days until first 28°F freezeDec 30

Aim to winterize your RV in Corona by December 20, roughly a week and a half before the median first 28°F freeze of December 30, which one fall in ten shows up by December 7. Year to year the date swings about 47 days, which is why the live outlook beats the calendar.

OUTLOOK

Typical first first 28°F freeze near Dec 30; local deadline about Dec 20. The live 10-day outlook loads here.

Local freeze dates for Corona

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Nov 27Dec 19Jan 17
28°F (hard freeze)Dec 7Dec 30Jan 23

NOAA station: Chino AP · 8.0 mi away · 650 ft elevation.

Numbers for Corona come from Chino AP, 8.0 miles away at 650 feet, where the medians fall 32°F by Dec 19, 28°F by Dec 30. That hard freeze has landed anywhere from Dec 7 to Jan 23, a swing of roughly 47 days. Spring's last 32°F freeze clears around Jan 17.

The freeze arrives in two steps in Corona: 32°F around Dec 19, then a hard 28°F near Dec 30. Year to year, the first 32°F night has fallen anywhere from Nov 27 to Jan 17 — about 51 days apart. Spring's final freeze lands near Jan 17 and as late as Feb 22, so that is when outdoor water and stored gear can safely come back online. Measurable snow is rare, so the freeze near Jan 17 — not snow load — drives the local prep list.

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

Corona freezes close to Eastvale (Dec 30) and close to Riverside (Dec 29) — a reminder that even nearby towns differ by days. Statewide, California prep dates run Jan 6 through Dec 27, which is why Corona gets its own number rather than a California-wide average. The same freeze also decides when to shut down your sprinklers and winterize a boat.

Other winter jobs in Corona

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

Sprinklers → Dec 20Frozen pipes → Nov 27Car battery → Dec 30Sump pump → Jan 17Boat → Dec 23Motorcycle → Dec 19

See the full Corona 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 Corona?
Wait until the last spring freeze has passed, which averages near Jan 17 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 Chino AP, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.