FrostList

When to Winterize Your RV in Washington, DC

ON TRACK132 days until first 28°F freezeNov 20

Aim to winterize your RV in Washington by November 10, roughly a week and a half before the median first 28°F freeze of November 20, which one fall in ten shows up by November 6. The early-odds date runs roughly 14 days ahead of the median, so build in that buffer.

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 Washington

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Oct 26Nov 8Nov 23
28°F (hard freeze)Nov 6Nov 20Dec 7
24°F (severe)Nov 16Dec 6Dec 28

NOAA station: Natl Arboretum Dc · 3.6 mi away · 50 ft elevation.

Numbers for Washington come from Natl Arboretum Dc, 3.6 miles away at 50 feet, where the medians fall 32°F by Nov 8, 28°F by Nov 20, 24°F by Dec 6. The 28°F freeze has come as early as Nov 6 and as late as Dec 7, a 31-day spread. Spring's last 32°F freeze clears around Mar 29. Snowfall averages 10 inches a year, first reaching an inch near December.

The freeze arrives in two steps in Washington: 32°F around Nov 8, then a hard 28°F near Nov 20. The 32°F date swings from Oct 26 at its earliest to Nov 23 at its latest, near 28 days. The last spring freeze averages Mar 29 and as late as Apr 11, which sets the safe window for reopening outdoor water and de-winterizing gear. At about 10 inches of snow a year, the freeze — not snow load — is the thing to plan around.

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

Washington freezes close to Alexandria (Nov 19) and close to Rockville (Nov 19) — a reminder that even nearby towns differ by days. Statewide, District of Columbia prep dates run Nov 10 through Nov 10, which is why Washington gets its own number rather than a District of Columbia-wide average. The same freeze also decides when to shut down your sprinklers and winterize a boat.

Other winter jobs in Washington

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

Sprinklers → Nov 10Frozen pipes → Oct 26Ice dams → Nov 15Car battery → Nov 20Snow blower → Nov 24Sump pump → Mar 29Boat → Nov 13Motorcycle → Nov 8

See the full Washington 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 Washington?
Wait until the last spring freeze has passed, which averages near Mar 29 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 Natl Arboretum Dc, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.