Professional RV winterization by rig size — travel trailers at the low end, Class A motorhomes at the top. DIY costs $20–$60 in antifreeze and a siphon kit.
KOAWhen to Winterize Your RV in Spokane Valley, WA
Spokane Valley's deadline to winterize your RV is October 17: the local first 28°F freeze runs October 27 on average and October 11 at its earliest (1991–2020 normals). Plan for the early end: the one-in-ten date lands about 16 days before the median.

Typical first first 28°F freeze near Oct 27; local deadline about Oct 17. The live 10-day outlook loads here.
Local freeze dates for Spokane Valley
| Threshold | Early (1-in-10) | Median | Late (9-in-10) |
|---|---|---|---|
| 32°F (light freeze) | Sep 30 | Oct 15 | Oct 31 |
| 28°F (hard freeze) | Oct 11 | Oct 27 | Nov 13 |
| 24°F (severe) | Oct 21 | Nov 8 | Nov 26 |
Bars span the early (1-in-10) to late (9-in-10) window for each freeze threshold; the dot marks the median year. The dashed line is the local prep deadline.
NOAA station: Spokane Felts Fld · 3.9 mi away · 1,953 ft elevation.
- Spokane Valley sits in the middle of the pack, with a mid-fall first freeze — don't let a mild stretch push the work later.
For Spokane Valley, the nearest NOAA station with freeze data is Spokane Felts Fld, 3.9 miles out at 1,953 feet. Median first-freeze dates there run 32°F by Oct 15, 28°F by Oct 27, 24°F by Nov 8. Year to year the 28°F date has ranged from Oct 11 to Nov 13 — about 33 days apart. Spring's last 32°F freeze clears around Apr 26. Snowfall averages 45 inches a year, first reaching an inch near November.
Spokane Valley usually sees its first 32°F night about Oct 15, with the first 28°F hard freeze close behind near Oct 27. That first freezing night has ranged from Sep 30 to Oct 31, roughly a 31-day spread. On the spring side, the last 32°F freeze clears around Apr 26 and as late as May 10 — the green light for reopening water and de-winterizing. Snow totals near 45 inches a year mean plowing and ice-dam control share the winter to-do list here.
Your rv checklist
- Drain the fresh, gray, and black tanks, then drain the water heater only after it has cooled and lost pressure.
- Bypass the water heater so you do not waste six gallons of antifreeze filling the tank.
- 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
- Use a water-pump converter kit to draw antifreeze straight from the jug through the plumbing.Helpful gear: Water pump converter kit — Recommended pick
- Pour a cup of antifreeze into each drain trap and the toilet to protect the seals.
- Fit a blow-out plug at the city-water inlet so you can clear that line too.Helpful gear: Blow-out plug — Recommended pick
- Remove batteries or put them on a maintainer, and store them off a cold concrete floor.
- Cover roof vents, close the propane, and set out traps or deterrents so mice do not move in.
What to have on hand
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RV winterization cost & key numbers
Verified national benchmarks; sources open in a new tab (nofollow).
Non-toxic propylene glycol antifreeze a typical rig needs ($5–$10 per gallon); large fifth wheels take 4–5. Add a gallon each for a dishwasher or washer.
RV LifestyleAntifreeze wasted if you skip the water-heater bypass — the tank swallows it before any reaches the plumbing. A bypass kit pays for itself the first season.
CamcoReplacement cost of a freeze-cracked RV water pump; fittings, the toilet valve and the city-water inlet crack first. Most RV policies exclude freeze damage from skipped winterization.
ProgressiveWhat this means locally
Spokane Valley freezes close to Spokane (Oct 27) and about a week ahead of Coeur d'Alene (Nov 1) — a reminder that even nearby towns differ by days. Statewide, Washington prep dates run Oct 6 through Dec 1, which is why Spokane Valley gets its own number rather than a Washington-wide average. The same freeze also decides when to shut down your sprinklers and winterize a boat. Keeping an eye on the rest of the county? The same local math is on our Tacoma page.
Other winter jobs in Spokane Valley
Every task below is dated to Spokane Valley's own freeze and snow normals.
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Frequently asked questions
At what temperature do RV pipes freeze?
How much RV antifreeze do I need?
Can I just use my RV furnace instead of winterizing?
How do I winterize an RV water heater?
When is it safe to de-winterize an RV in Spokane Valley?
Do I need to winterize an RV stored indoors?
How much does it cost to winterize an RV?
What happens if I skip winterizing the RV?
RV Winterization: related searches
Searches this guide answers: RV antifreeze how many gallons, water heater bypass kit, blow out RV lines with air, and RV winterization service near me.
Data: NOAA 1991–2020 normals via Spokane Felts Fld, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 25, 2026.