FrostList

When to Prevent Frozen Pipes in Florissant, MO

ON TRACK116 days until first freezing night (32°F)Nov 4

The first freezing night in Florissant averages November 4 and can arrive as early as October 23 (1991–2020 normals), and the real danger starts when lows drop into the low 20s. Year to year the date swings about 28 days, which is why the live outlook beats the calendar.

OUTLOOK

Typical first first freezing night (32°F) near Nov 4; local deadline about Oct 23. The live 10-day outlook loads here.

Local freeze dates for Florissant

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Oct 23Nov 4Nov 18
28°F (hard freeze)Nov 2Nov 13Nov 30
24°F (severe)Nov 8Nov 24Dec 11

NOAA station: St Louis Lambert Intl AP · 3.7 mi away · 531 ft elevation.

Numbers for Florissant come from St Louis Lambert Intl AP, 3.7 miles away at 531 feet, where the medians fall 32°F by Nov 4, 28°F by Nov 13, 24°F by Nov 24. The 28°F freeze has come as early as Nov 2 and as late as Nov 30, a 28-day spread. Spring's last 32°F freeze clears around Apr 2. Snowfall averages 17 inches a year, first reaching an inch near December.

In Florissant, freezing nights (32°F) typically begin around Nov 4 and the first hard freeze (28°F) follows near Nov 13. Year to year, the first 32°F night has fallen anywhere from Oct 23 to Nov 18 — about 26 days apart. Spring's final freeze lands near Apr 2 and as late as Apr 17, so that is when outdoor water and stored gear can safely come back online. Snowfall averages roughly 17 inches a year — enough that a working snow blower and a clear roof edge earn their keep.

Your frozen pipes checklist

  1. Disconnect, drain, and store garden hoses, then shut off and drain any interior valves that feed outdoor faucets.
  2. Insulate exposed pipes in the garage, crawl space, and along exterior walls with foam sleeves rated for the pipe size.
    Helpful gear: Foam pipe insulation sleeves — Recommended pick
  3. On nights in the low 20s, let a pencil-thin stream of water drip from the faucet farthest from where the line enters.
  4. Open cabinet doors under kitchen and bathroom sinks on outside walls so household heat reaches the plumbing.
  5. Add self-regulating heat cable to the runs most likely to freeze, such as a pipe in an unheated garage.
    Helpful gear: Self-regulating heat cable — Recommended pick
  6. Cap outdoor faucets with insulated covers once the hoses are off.
    Helpful gear: Outdoor faucet covers — Recommended pick
  7. Know where your main shutoff is and confirm it turns; a fast shutoff limits water damage if a line lets go.
  8. If you travel, keep the thermostat at 55°F or higher and ask someone to check the house during a cold snap.
    Helpful gear: Wi-Fi water leak sensor — Recommended pick

What to have on hand

Foam pipe insulation sleeves
Split foam tubing for exposed pipes in crawl spaces and garages.
Recommended pick
Self-regulating heat cable
Thermostatic cable that warms vulnerable runs only when it is cold.
Recommended pick
Outdoor faucet covers
Insulated caps for hose bibs once the hoses come off.
Recommended pick
Wi-Fi water leak sensor
Puck that pings your phone the moment it senses water.
Recommended pick

What this means locally

Compared with nearby cities, Florissant's first-freeze date near Nov 4 sits later than St. Charles (Oct 29) and close to St. Louis (Nov 4). Missouri's deadlines span Sep 30 to Oct 24 statewide — one date for all of Missouri would be off by weeks for Florissant. Once you know Florissant's freeze date, use it to shut down your sprinklers and check your car battery too.

Other winter jobs in Florissant

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

Sprinklers → Nov 3Ice dams → Nov 15Car battery → Nov 13Snow blower → Nov 24Sump pump → Apr 2RV → Nov 3Boat → Nov 6Motorcycle → Nov 4

See the full Florissant winter checklist, in order →

Frequently asked questions

At what temperature do pipes freeze?
Pipes generally come under risk when the temperature outside falls to about 20°F, the threshold many guides use for taking action. Pipes in unheated or exterior-wall spaces freeze sooner than well-insulated interior runs. Wind and poor insulation lower the effective temperature, so a windy night in the mid-20s can be as risky as a still night in the low 20s.
Should I drip my faucets tonight in Florissant?
If the overnight low is forecast at or below about 20°F, letting a thin stream run from the faucet farthest along the line is a low-cost precaution. Moving water is slower to freeze and relieves pressure. Check tonight's low against the live outlook above; freezing nights here typically begin around Nov 4.
How long does it take for pipes to freeze?
There is no fixed clock; it depends on pipe location, insulation, and how far below freezing the air drops. An exposed pipe in a windy, unheated space can freeze in a matter of hours during a hard cold snap, while a protected interior pipe may never reach freezing. The colder and windier it is, the faster it happens.
Which pipes freeze first?
The most exposed pipes freeze first: outdoor hose bibs, and lines in unheated garages, crawl spaces, attics, and along exterior walls. Pipes under sinks on outside walls are common trouble spots. That is why disconnecting hoses and opening cabinet doors on cold nights are two of the highest-value steps.
Does homeowners insurance cover burst pipes?
Sudden, accidental water damage from a frozen pipe is often covered, but insurers may deny a claim if the home was left unheated or the damage is judged to be from neglect. Coverage varies by policy. Keeping the heat on and taking reasonable precautions helps protect both your home and your claim.
What temperature should I keep my house if I'm away?
A common recommendation is to keep the thermostat no lower than 55°F while you are away so interior walls stay warm enough to protect the plumbing. Leaving cabinet doors open and having someone check the house during a cold snap adds a margin of safety, especially for pipes on exterior walls.

Data: NOAA 1991–2020 normals via St Louis Lambert Intl AP, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.