FrostList

When to Winterize Your RV in Gresham, OR

ON TRACK157 days until first 28°F freezeDec 15

In a typical year, winterize your RV in Gresham by December 5. The median first 28°F hard freeze at Gresham's NOAA station is December 15 (1991–2020 normals); one year in ten it arrives as early as November 15. The early-to-late range spans roughly 80 days, so treat the median as a midpoint, not a promise.

OUTLOOK

Typical first first 28°F freeze near Dec 15; local deadline about Dec 5. The live 10-day outlook loads here.

Local freeze dates for Gresham

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Oct 30Nov 20Dec 17
28°F (hard freeze)Nov 15Dec 15Feb 3
24°F (severe)Nov 30Jan 1Feb 13

NOAA station: Portland Troutdale AP · 3.7 mi away · 29 ft elevation.

Gresham draws its numbers from Portland Troutdale AP, 29 feet up and 3.7 miles away. Its median first-freeze dates are 32°F by Nov 20, 28°F by Dec 15, 24°F by Jan 1. That hard freeze has landed anywhere from Nov 15 to Feb 3, a swing of roughly 80 days. Spring's last 32°F freeze clears around Mar 16. Snowfall averages 3 inches a year, first reaching an inch near December.

Gresham usually sees its first 32°F night about Nov 20, with the first 28°F hard freeze close behind near Dec 15. The 32°F date swings from Oct 30 at its earliest to Dec 17 at its latest, near 48 days. The last spring freeze averages Mar 16 and as late as Apr 12, which sets the safe window for reopening outdoor water and de-winterizing gear. At about 3 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

Gresham freezes about a week ahead of Portland (Dec 20) and later than Lake Oswego (Dec 8) — a reminder that even nearby towns differ by days. Statewide, Oregon prep dates run Sep 24 through Dec 11, which is why Gresham gets its own number rather than a Oregon-wide average. The same freeze also decides when to shut down your sprinklers and winterize a boat.

Other winter jobs in Gresham

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

Sprinklers → Dec 5Frozen pipes → Oct 30Ice dams → Nov 15Car battery → Dec 15Snow blower → Nov 24Sump pump → Mar 16Boat → Dec 8Motorcycle → Nov 20

See the full Gresham 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 Gresham?
Wait until the last spring freeze has passed, which averages near Mar 16 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 Portland Troutdale AP, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.