FrostList

When to Winterize Your RV in Hattiesburg, MS

ON TRACK142 days until first 28°F freezeNov 30

Aim to winterize your RV in Hattiesburg by November 20, roughly a week and a half before the median first 28°F freeze of November 30, which one fall in ten shows up by November 10. Cold deepens quickly here — only about 15 days separate the first frost from that hard freeze.

OUTLOOK

Typical first first 28°F freeze near Nov 30; local deadline about Nov 20. The live 10-day outlook loads here.

Local freeze dates for Hattiesburg

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Nov 1Nov 15Dec 4
28°F (hard freeze)Nov 10Nov 30Jan 4
24°F (severe)Nov 26Dec 28Jan 27

NOAA station: Hattiesburg Chain Muni AP · 3.8 mi away · 151 ft elevation.

For Hattiesburg, the nearest NOAA station with freeze data is Hattiesburg Chain Muni AP, 3.8 miles out at 151 feet. Median first-freeze dates there run 32°F by Nov 15, 28°F by Nov 30, 24°F by Dec 28. Year to year the 28°F date has ranged from Nov 10 to Jan 4 — about 55 days apart. Spring's last 32°F freeze clears around Mar 8. Snowfall averages 1 inches a year.

In Hattiesburg, freezing nights (32°F) typically begin around Nov 15 and the first hard freeze (28°F) follows near Nov 30. That first freezing night has ranged from Nov 1 to Dec 4, roughly a 33-day spread. On the spring side, the last 32°F freeze clears around Mar 8 and as late as Mar 28 — 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 Mar 8.

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, Hattiesburg's first-freeze date near Nov 30 sits later than Gulfport (Jan 2) and later than Biloxi (Jan 2). Mississippi's deadlines span Nov 17 to Dec 23 statewide — one date for all of Mississippi would be off by weeks for Hattiesburg. Once you know Hattiesburg's freeze date, use it to shut down your sprinklers and winterize a boat too.

Other winter jobs in Hattiesburg

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

Sprinklers → Nov 20Frozen pipes → Nov 1Car battery → Nov 30Sump pump → Mar 8Boat → Nov 23Motorcycle → Nov 15

See the full Hattiesburg 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 Hattiesburg?
Wait until the last spring freeze has passed, which averages near Mar 8 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 Hattiesburg Chain Muni AP, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.