FrostList

When to Prevent Frozen Pipes in Bismarck, ND

ON TRACK81 days until first freezing night (32°F)Sep 30

Freezing nights in Bismarck begin around September 30 in a typical year, and as early as September 16 one fall in ten (1991–2020 NOAA normals); pipes come under real risk once lows reach the low 20s. It's a short step from frost to a hard freeze: roughly 9 days on average.

OUTLOOK

Typical first first freezing night (32°F) near Sep 30; local deadline about Sep 16. The live 10-day outlook loads here.

Local freeze dates for Bismarck

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Sep 16Sep 30Oct 13
28°F (hard freeze)Sep 25Oct 9Oct 22
24°F (severe)Oct 2Oct 18Nov 1

NOAA station: Bismarck 2.4 Nnw · 1.9 mi away · 1,831 ft elevation.

Bismarck draws its numbers from Bismarck 2.4 Nnw, 1,831 feet up and 1.9 miles away. Its median first-freeze dates are 32°F by Sep 30, 28°F by Oct 9, 24°F by Oct 18. That hard freeze has landed anywhere from Sep 25 to Oct 22, a swing of roughly 27 days. Spring's last 32°F freeze clears around May 10. Snowfall averages 50 inches a year, first reaching an inch near October.

Bismarck usually sees its first 32°F night about Sep 30, with the first 28°F hard freeze close behind near Oct 9. Year to year, the first 32°F night has fallen anywhere from Sep 16 to Oct 13 — about 27 days apart. Spring's final freeze lands near May 10 and as late as May 23, so that is when outdoor water and stored gear can safely come back online. With about 50 inches of snow a year, roof, snow-blower, and ice-dam prep all belong on the same calendar.

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, Bismarck's first-freeze date near Sep 30 sits close to Minot (Oct 1) and close to Pierre (Oct 3). North Dakota's deadlines span Sep 16 to Sep 22 statewide — one date for all of North Dakota would be off by weeks for Bismarck. Once you know Bismarck's freeze date, use it to shut down your sprinklers and check your car battery too.

Other winter jobs in Bismarck

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

Sprinklers → Sep 29Ice dams → Sep 15Car battery → Oct 9Snow blower → Sep 24Sump pump → May 10RV → Sep 29Boat → Oct 2Motorcycle → Sep 30

See the full Bismarck 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 Bismarck?
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 Sep 30.
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 Bismarck 2.4 Nnw, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.