Average US homeowners-insurance claim for water damage and freezing (2019–2023). Roughly 1 in 60 insured homes files one every year.
Insurance Information InstituteWhen to Prevent Frozen Pipes in Redwood City, CA
ON TRACK154 days until first freezing night (32°F)Dec 12
In Redwood City, plan for freezing nights from about December 12 onward — one year in ten by November 24 — and treat any low in the low 20s as a pipe-risk night. Cold deepens quickly here — only about 14 days separate the first frost from that hard freeze.
Nov 24Local deadline
Dec 12First freezing night
41 days28°F window spread
Station 0.6 miSnow per season
OUTLOOK
Typical first first freezing night (32°F) near Dec 12; local deadline about Nov 24. The live 10-day outlook loads here.
Local freeze dates for Redwood City
| Threshold | Early (1-in-10) | Median | Late (9-in-10) |
|---|---|---|---|
| 32°F (light freeze) | Nov 24 | Dec 12 | Jan 14 |
| 28°F (hard freeze) | Dec 5 | Dec 26 | Jan 15 |
Bars span the early (1-in-10) to late (9-in-10) window for each freeze threshold; the dot marks the median year. The dashed line is the local prep deadline.
NOAA station: Redwood City · 0.6 mi away · 31 ft elevation.
- Hard freezes are rare and late in Redwood City, which is exactly why they catch people off guard when they do come.
- The 41-day gap between the earliest and latest freeze dates here is wide, so the live outlook matters more than the calendar.
Redwood City draws its numbers from Redwood City, 31 feet up and 0.6 miles away. Its median first-freeze dates are 32°F by Dec 12, 28°F by Dec 26. Year to year the 28°F date has ranged from Dec 5 to Jan 15 — about 41 days apart. Spring's last 32°F freeze clears around Jan 17.
In Redwood City, freezing nights (32°F) typically begin around Dec 12 and the first hard freeze (28°F) follows near Dec 26. That first freezing night has ranged from Nov 24 to Jan 14, roughly a 51-day spread. On the spring side, the last 32°F freeze clears around Jan 17 and as late as Feb 16 — 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 Jan 17.
Your frozen pipes checklist
- Disconnect, drain, and store garden hoses, then shut off and drain any interior valves that feed outdoor faucets.
- 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
- On nights in the low 20s, let a pencil-thin stream of water drip from the faucet farthest from where the line enters.
- Open cabinet doors under kitchen and bathroom sinks on outside walls so household heat reaches the plumbing.
- 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
- Cap outdoor faucets with insulated covers once the hoses are off.Helpful gear: Outdoor faucet covers — Recommended pick
- Know where your main shutoff is and confirm it turns; a fast shutoff limits water damage if a line lets go.
- 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
As an Amazon Associate we may earn from qualifying purchases. Product picks are editorial; links do not change what you pay.
Foam pipe insulation sleeves
Split foam tubing for exposed pipes in crawl spaces and garages.
Recommended pickSelf-regulating heat cable
Thermostatic cable that warms vulnerable runs only when it is cold.
Recommended pickOutdoor faucet covers
Insulated caps for hose bibs once the hoses come off.
Recommended pickWi-Fi water leak sensor
Puck that pings your phone the moment it senses water.
Recommended pickFrozen pipe damage: the key numbers
Verified national benchmarks; sources open in a new tab (nofollow).
The outdoor temperature at which uninsulated pipes in unheated spaces begin to freeze, per Building Research Council field tests — the widely used "temperature alert threshold".
University of IllinoisHow much water a 1/8-inch pipe crack can release into your home. Ice blockage drives trapped water pressure from ~50 PSI to over 4,000 PSI before the pipe fails.
IBHSCost of self-seal foam pipe insulation per linear foot — the cheapest protection there is. Keep the thermostat at 55°F or higher, even when away.
American Red CrossWhat this means locally
Against its neighbors, Redwood City (first freeze Dec 12) runs later than Palo Alto (Dec 7) and about a week ahead of San Mateo (Dec 26). Across California, local prep deadlines in our data range from Oct 17 to Dec 23, so a statewide rule of thumb would miss Redwood City by weeks. In Redwood City, that same cold is your cue to shut down your sprinklers and check your car battery. Keeping an eye on the rest of the county? The same local math is on our Redondo Beach and Rialto pages.
Other winter jobs in Redwood City
Every task below is dated to Redwood City's own freeze and snow normals.
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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 Redwood City?
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 Dec 12.
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.
Frozen Pipe Protection: related searches
Searches this guide answers: what temperature do pipes freeze, heat tape for pipes, letting faucets drip in winter, and how to keep pipes from freezing in a crawl space.
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Data: NOAA 1991–2020 normals via Redwood City, live outlook by Open-Meteo. Sources · Methodology. Last updated: July 25, 2026.