FrostList

When to Prevent Frozen Pipes in Lake Oswego, OR

ON TRACK130 days until first freezing night (32°F)Nov 18

In Lake Oswego, plan for freezing nights from about November 18 onward — one year in ten by October 30 — and treat any low in the low 20s as a pipe-risk night. Cold deepens quickly here — only about 20 days separate the first frost from that hard freeze.

OUTLOOK

Typical first first freezing night (32°F) near Nov 18; local deadline about Oct 30. The live 10-day outlook loads here.

Local freeze dates for Lake Oswego

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Oct 30Nov 18Dec 12
28°F (hard freeze)Nov 16Dec 8Jan 5
24°F (severe)Nov 29Dec 26Feb 4

NOAA station: Oregon City · 5.5 mi away · 167 ft elevation.

The reference station for Lake Oswego is Oregon City (5.5 mi, 167 ft). First freeze there: 32°F by Nov 18, 28°F by Dec 8, 24°F by Dec 26. Year to year the 28°F date has ranged from Nov 16 to Jan 5 — about 50 days apart. Spring's last 32°F freeze clears around Mar 18. Snowfall averages 4 inches a year, first reaching an inch near January.

The freeze arrives in two steps in Lake Oswego: 32°F around Nov 18, then a hard 28°F near Dec 8. That first freezing night has ranged from Oct 30 to Dec 12, roughly a 43-day spread. On the spring side, the last 32°F freeze clears around Mar 18 and as late as Apr 11 — the green light for reopening water and de-winterizing. Only about 4 inches of snow falls in a typical year, so cold protection outranks snow removal.

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, Lake Oswego's first-freeze date near Nov 18 sits later than Tigard (Nov 6) and about a week ahead of Portland (Dec 1). Oregon's deadlines span Sep 3 to Nov 11 statewide — one date for all of Oregon would be off by weeks for Lake Oswego. Once you know Lake Oswego's freeze date, use it to shut down your sprinklers and check your car battery too.

Other winter jobs in Lake Oswego

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

Sprinklers → Nov 28Ice dams → Dec 16Car battery → Dec 8Snow blower → Dec 25Sump pump → Mar 18RV → Nov 28Boat → Dec 1Motorcycle → Nov 18

See the full Lake Oswego 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 Lake Oswego?
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 18.
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 Oregon City, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.