FrostList

When to Winterize Your RV in Hagerstown, MD

ON TRACK121 days until first 28°F freezeNov 9

Hagerstown's median first 28°F hard freeze is November 9 (1991–2020 NOAA normals), and it can strike as early as October 26 — so winterize your RV in Hagerstown by October 30. The early-to-late range spans roughly 30 days, so treat the median as a midpoint, not a promise.

OUTLOOK

Typical first first 28°F freeze near Nov 9; local deadline about Oct 30. The live 10-day outlook loads here.

Local freeze dates for Hagerstown

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Oct 14Oct 28Nov 11
28°F (hard freeze)Oct 26Nov 9Nov 25
24°F (severe)Nov 6Nov 23Dec 11

NOAA station: Hagerstown 1 E · 1.2 mi away · 532 ft elevation.

Hagerstown draws its numbers from Hagerstown 1 E, 532 feet up and 1.2 miles away. Its median first-freeze dates are 32°F by Oct 28, 28°F by Nov 9, 24°F by Nov 23. The 28°F freeze has come as early as Oct 26 and as late as Nov 25, a 30-day spread. Spring's last 32°F freeze clears around Apr 11. Snowfall averages 33 inches a year, first reaching an inch near December.

Expect the first frost near Oct 28 in Hagerstown and the first hard freeze by about Nov 9. The 32°F date swings from Oct 14 at its earliest to Nov 11 at its latest, near 28 days. The last spring freeze averages Apr 11 and as late as Apr 27, which sets the safe window for reopening outdoor water and de-winterizing gear. About 33 inches of snow a year is enough to justify servicing the snow blower and watching the eaves.

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, Hagerstown's first-freeze date near Nov 9 sits about a week ahead of Frederick (Nov 21) and later than Leesburg (Nov 5). Maryland's deadlines span Oct 22 to Nov 25 statewide — one date for all of Maryland would be off by weeks for Hagerstown. Once you know Hagerstown's freeze date, use it to shut down your sprinklers and winterize a boat too.

Other winter jobs in Hagerstown

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

Sprinklers → Oct 30Frozen pipes → Oct 14Ice dams → Nov 15Car battery → Nov 9Snow blower → Nov 24Sump pump → Apr 11Boat → Nov 2Motorcycle → Oct 28

See the full Hagerstown 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 Hagerstown?
Wait until the last spring freeze has passed, which averages near Apr 11 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 Hagerstown 1 E, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.