FrostList

When to Winterize Your RV in St. George, UT

ON TRACK132 days until first 28°F freezeNov 20

St. George's deadline to winterize your RV is November 10: the local first 28°F freeze runs November 20 on average and November 7 at its earliest (1991–2020 normals). It's a short step from frost to a hard freeze: roughly 10 days on average.

OUTLOOK

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

Local freeze dates for St. George

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Oct 27Nov 10Nov 22
28°F (hard freeze)Nov 7Nov 20Dec 3
24°F (severe)Nov 18Dec 1Dec 18

NOAA station: St George · 2.6 mi away · 2,857 ft elevation.

For St. George, the nearest NOAA station with freeze data is St George, 2.6 miles out at 2,857 feet. Median first-freeze dates there run 32°F by Nov 10, 28°F by Nov 20, 24°F by Dec 1. The 28°F freeze has come as early as Nov 7 and as late as Dec 3, a 26-day spread. Spring's last 32°F freeze clears around Mar 14. Snowfall averages 1 inches a year.

Expect the first frost near Nov 10 in St. George and the first hard freeze by about Nov 20. Year to year, the first 32°F night has fallen anywhere from Oct 27 to Nov 22 — about 26 days apart. Spring's final freeze lands near Mar 14 and as late as Apr 6, so that is when outdoor water and stored gear can safely come back online. Measurable snow is rare, so the freeze near Mar 14 — 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

Compared with nearby cities, St. George's first-freeze date near Nov 20 sits about a week ahead of North Las Vegas (Dec 21) and about a week ahead of Henderson (Dec 26). Utah's deadlines span Oct 4 to Nov 10 statewide — one date for all of Utah would be off by weeks for St. George. Once you know St. George's freeze date, use it to shut down your sprinklers and winterize a boat too.

Other winter jobs in St. George

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

Sprinklers → Nov 10Frozen pipes → Oct 27Car battery → Nov 20Sump pump → Mar 14Boat → Nov 13Motorcycle → Nov 10

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