FrostList

When to Winterize Your RV in Decatur, AL

ON TRACK131 days until first 28°F freezeNov 19

Aim to winterize your RV in Decatur by November 9, roughly a week and a half before the median first 28°F freeze of November 19, which one fall in ten shows up by November 4. The early-odds date runs roughly 15 days ahead of the median, so build in that buffer.

OUTLOOK

Typical first first 28°F freeze near Nov 19; local deadline about Nov 9. The live 10-day outlook loads here.

Local freeze dates for Decatur

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Oct 26Nov 7Nov 26
28°F (hard freeze)Nov 4Nov 19Dec 10
24°F (severe)Nov 12Dec 3Jan 1

NOAA station: Decatur 4Se · 3.5 mi away · 550 ft elevation.

Decatur draws its numbers from Decatur 4Se, 550 feet up and 3.5 miles away. Its median first-freeze dates are 32°F by Nov 7, 28°F by Nov 19, 24°F by Dec 3. That hard freeze has landed anywhere from Nov 4 to Dec 10, a swing of roughly 36 days. Spring's last 32°F freeze clears around Mar 26. Snowfall averages 1 inches a year.

The freeze arrives in two steps in Decatur: 32°F around Nov 7, then a hard 28°F near Nov 19. The 32°F date swings from Oct 26 at its earliest to Nov 26 at its latest, near 31 days. The last spring freeze averages Mar 26 and as late as Apr 9, which sets the safe window for reopening outdoor water and de-winterizing gear. Snow barely registers here; the freeze date, around Mar 26, is the one that matters.

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

Against its neighbors, Decatur (first freeze Nov 19) runs close to Madison (Nov 20) and close to Huntsville (Nov 20). Across Alabama, local prep deadlines in our data range from Nov 4 to Dec 20, so a statewide rule of thumb would miss Decatur by weeks. In Decatur, that same cold is your cue to shut down your sprinklers and winterize a boat.

Other winter jobs in Decatur

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

Sprinklers → Nov 9Frozen pipes → Oct 26Car battery → Nov 19Sump pump → Mar 26Boat → Nov 12Motorcycle → Nov 7

See the full Decatur 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 Decatur?
Wait until the last spring freeze has passed, which averages near Mar 26 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 Decatur 4Se, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.