FrostList

When to Prevent Frozen Pipes in Casper, WY

ON TRACK80 days until first freezing night (32°F)Sep 29

The first freezing night in Casper averages September 29 and can arrive as early as September 14 (1991–2020 normals), and the real danger starts when lows drop into the low 20s. The early-to-late range spans roughly 32 days, so treat the median as a midpoint, not a promise.

OUTLOOK

Typical first first freezing night (32°F) near Sep 29; local deadline about Sep 14. The live 10-day outlook loads here.

Local freeze dates for Casper

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Sep 14Sep 29Oct 12
28°F (hard freeze)Sep 21Oct 6Oct 23
24°F (severe)Sep 30Oct 17Nov 1

NOAA station: Casper Wwtp · 1.1 mi away · 5,097 ft elevation.

The reference station for Casper is Casper Wwtp (1.1 mi, 5,097 ft). First freeze there: 32°F by Sep 29, 28°F by Oct 6, 24°F by Oct 17. Year to year the 28°F date has ranged from Sep 21 to Oct 23 — about 32 days apart. Spring's last 32°F freeze clears around May 10. Snowfall averages 72 inches a year, first reaching an inch near September.

Expect the first frost near Sep 29 in Casper and the first hard freeze by about Oct 6. Year to year, the first 32°F night has fallen anywhere from Sep 14 to Oct 12 — about 28 days apart. Spring's final freeze lands near May 10 and as late as May 24, so that is when outdoor water and stored gear can safely come back online. With about 72 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

Against its neighbors, Casper (first freeze Sep 29) runs close to Cheyenne (Oct 1) and about a week ahead of Fort Collins (Oct 7). Across Wyoming, local prep deadlines in our data range from Sep 14 to Sep 17, so a statewide rule of thumb would miss Casper by weeks. In Casper, that same cold is your cue to shut down your sprinklers and check your car battery.

Other winter jobs in Casper

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

Sprinklers → Sep 26Ice dams → Aug 16Car battery → Oct 6Snow blower → Aug 25Sump pump → May 10RV → Sep 26Boat → Sep 29Motorcycle → Sep 29

See the full Casper 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 Casper?
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 29.
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 Casper Wwtp, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.