Will Pipes Freeze in King County, WA? 4 nights a Year
Freeze nights in King County
In a normal year King County, WA gets 4 nights at or below 20°F, the point where bare pipes in a garage, attic or outside wall start to freeze. That is more than 15% of US counties.
Risk level: Occasional. The risk season runs December to February, worst in January.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 78 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 4 nights |
| Insulated pipe in unheated space | 10°F | none |
| Inside the heated house | 0°F | none |
Foam-sleeving a bare pipe in unheated space takes it from 4 nights of risk to none. A 12 ft heat-tape kit runs $17 to $37; an average burst-pipe repair is about $500.
Month by month
Nights at or below 20°F in a normal year.
First 32°F night is usually around 11/01, last around 04/23. For 20°F: 12/21 to 01/26.
How cold King County nights get
Average winter (Dec-Feb) low: 32°F; the coldest month, December, averages 32°F overnight. 8 months normally bring at least one night below 32°F (Jan, Feb, Mar, Apr, May, Oct, Nov, Dec).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 33°F | 33°F | 34°F | 37°F | 43°F | 48°F | 52°F | 53°F | 49°F | 42°F | 36°F | 32°F |
King County next to its neighbours
Snohomish County, WA, 63 km north, gets 6 nights below 20°F to King County's 4 nights. Kitsap County, WA, 63 km west, gets 2 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| King County, WA | - | 78 nights | 4 nights | 33°F |
| Pierce County, WA | 54 km southwest | 70 nights | 4 nights | 33°F |
| Snohomish County, WA | 63 km north | 82 nights | 6 nights | 32°F |
| Kitsap County, WA | 63 km west | 46 nights | 2 nights | 35°F |
| Kittitas County, WA | 96 km southeast | 148 nights | 35 nights | 23°F |
| Island County, WA | 97 km northwest | 28 nights | 1 night | 37°F |
| Thurston County, WA | 97 km southwest | 70 nights | 6 nights | 34°F |
King County within WA
King County ranks 29 of 39 WA counties for nights below 20°F. The most is Ferry County, WA at 62 nights, with a 18°F average winter low. The fewest is Island County, WA: 1 night, winter lows near 37°F. At 2,283 ft, King County sits 663 ft above the state's median county elevation of 1,620 ft.
What to do here
- Keep a night-of routine: drip, open cabinets, keep the heat at 55F or above.
- Foam-sleeve any pipe in the garage or crawlspace once; it is cheap and lasts years.
Whether foam sleeves are enough here: insulate or heat tape?.
Where this comes from
NOAA 1991-2020 climate normals, blended from 3 nearby stations and adjusted for elevation; closest is Cedar Lake, WA, 10 km away (fair match). A normal year, not tonight's forecast: check the forecast low for the night itself. Why elevation is part of the blend: how county numbers are made.