FrostList

When to Winterize Your RV in Hillsboro, OR

ON TRACK124 days until first 28°F freezeNov 12

Hillsboro's median first 28°F hard freeze is November 12 (1991–2020 NOAA normals), and it can strike as early as October 20 — so winterize your RV in Hillsboro by November 2. Cold deepens quickly here — only about 20 days separate the first frost from that hard freeze.

OUTLOOK

Typical first first 28°F freeze near Nov 12; local deadline about Nov 2. The live 10-day outlook loads here.

Local freeze dates for Hillsboro

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Oct 3Oct 23Nov 18
28°F (hard freeze)Oct 20Nov 12Dec 10
24°F (severe)Nov 4Dec 1Jan 11

NOAA station: Portland-Hillsboro AP · 2.3 mi away · 204 ft elevation.

Hillsboro draws its numbers from Portland-Hillsboro AP, 204 feet up and 2.3 miles away. Its median first-freeze dates are 32°F by Oct 23, 28°F by Nov 12, 24°F by Dec 1. The 28°F freeze has come as early as Oct 20 and as late as Dec 10, a 51-day spread. Spring's last 32°F freeze clears around Apr 16. Snowfall averages 3 inches a year, first reaching an inch near December.

The freeze arrives in two steps in Hillsboro: 32°F around Oct 23, then a hard 28°F near Nov 12. That first freezing night has ranged from Oct 3 to Nov 18, roughly a 46-day spread. On the spring side, the last 32°F freeze clears around Apr 16 and as late as May 3 — 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 Apr 16.

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, Hillsboro's first-freeze date near Nov 12 sits about a week ahead of Beaverton (Dec 21) and about a week ahead of Tigard (Nov 30). Oregon's deadlines span Sep 24 to Dec 11 statewide — one date for all of Oregon would be off by weeks for Hillsboro. Once you know Hillsboro's freeze date, use it to shut down your sprinklers and winterize a boat too.

Other winter jobs in Hillsboro

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

Sprinklers → Nov 2Frozen pipes → Oct 3Car battery → Nov 12Sump pump → Apr 16Boat → Nov 5Motorcycle → Oct 23

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