FrostList

When to Prevent Frozen Pipes in Hillsboro, OR

ON TRACK104 days until first freezing night (32°F)Oct 23

The first freezing night in Hillsboro averages October 23 and can arrive as early as October 3 (1991–2020 normals), and the real danger starts when lows drop into the low 20s. 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 Oct 23; local deadline about Oct 3. The live 10-day outlook loads here.

Local freeze dates for Hillsboro

ThresholdEarly (1-in-10)MedianLate (9-in-10)
32°F (light freeze)Oct 3Oct 23Nov 18
28°F (hard freeze)Oct 20Nov 12Dec 10
24°F (severe)Nov 4Dec 1Jan 11

NOAA station: Portland-Hillsboro AP · 2.3 mi away · 204 ft elevation.

Hillsboro draws its numbers from Portland-Hillsboro AP, 204 feet up and 2.3 miles away. Its median first-freeze dates are 32°F by Oct 23, 28°F by Nov 12, 24°F by Dec 1. The 28°F freeze has come as early as Oct 20 and as late as Dec 10, a 51-day spread. Spring's last 32°F freeze clears around Apr 16. Snowfall averages 3 inches a year, first reaching an inch near December.

The freeze arrives in two steps in Hillsboro: 32°F around Oct 23, then a hard 28°F near Nov 12. That first freezing night has ranged from Oct 3 to Nov 18, roughly a 46-day spread. On the spring side, the last 32°F freeze clears around Apr 16 and as late as May 3 — the green light for reopening water and de-winterizing. With almost no snow in a normal year, cold — not plowing — sets the calendar, and it centers on Apr 16.

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, Hillsboro's first-freeze date near Oct 23 sits about a week ahead of Beaverton (Dec 5) and about a week ahead of Tigard (Nov 6). Oregon's deadlines span Sep 3 to Nov 11 statewide — one date for all of Oregon would be off by weeks for Hillsboro. Once you know Hillsboro's freeze date, use it to shut down your sprinklers and check your car battery too.

Other winter jobs in Hillsboro

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

Sprinklers → Nov 2Car battery → Nov 12Sump pump → Apr 16RV → Nov 2Boat → Nov 5Motorcycle → Oct 23

See the full Hillsboro 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 Hillsboro?
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 Oct 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 Portland-Hillsboro AP, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 11, 2026.