FrostList

When to Prevent Frozen Pipes in Shoreline, WA

ON TRACK135 days until first freezing night (32°F)Nov 23

In Shoreline, plan for freezing nights from about November 23 onward — one year in ten by November 4 — and treat any low in the low 20s as a pipe-risk night. It's a short step from frost to a hard freeze: roughly 18 days on average.

OUTLOOK

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

Local freeze dates for Shoreline

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Nov 4Nov 23Dec 16
28°F (hard freeze)Nov 17Dec 11Jan 17
24°F (severe)Nov 27Dec 24Feb 8

NOAA station: Seattle Sand Pt Wsfo · 6.2 mi away · 60 ft elevation.

The reference station for Shoreline is Seattle Sand Pt Wsfo (6.2 mi, 60 ft). First freeze there: 32°F by Nov 23, 28°F by Dec 11, 24°F by Dec 24. The 28°F freeze has come as early as Nov 17 and as late as Jan 17, a 61-day spread. Spring's last 32°F freeze clears around Mar 8. Snowfall averages 4 inches a year, first reaching an inch near December.

Expect the first frost near Nov 23 in Shoreline and the first hard freeze by about Dec 11. Year to year, the first 32°F night has fallen anywhere from Nov 4 to Dec 16 — about 42 days apart. Spring's final freeze lands near Mar 8 and as late as Mar 29, so that is when outdoor water and stored gear can safely come back online. Snow is light here, near 4 inches a year, so pipe and battery cold usually matters more than plowing.

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, Shoreline's first-freeze date near Nov 23 sits later than Edmonds (Nov 17) and close to Kirkland (Nov 23). Washington's deadlines span Sep 23 to Nov 6 statewide — one date for all of Washington would be off by weeks for Shoreline. Once you know Shoreline's freeze date, use it to shut down your sprinklers and check your car battery too.

Other winter jobs in Shoreline

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

Sprinklers → Dec 1Ice dams → Nov 15Car battery → Dec 11Snow blower → Nov 24Sump pump → Mar 8RV → Dec 1Boat → Dec 4Motorcycle → Nov 23

See the full Shoreline 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 Shoreline?
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 23.
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 Seattle Sand Pt Wsfo, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.