Will Pipes Freeze in Washington County, OR? 4 nights a Year
Freeze nights in Washington County
In a normal year Washington County, OR 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 | 60 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 4 nights |
| Insulated pipe in unheated space | 10°F | under 1 night |
| Inside the heated house | 0°F | none |
Foam-sleeving a bare pipe in unheated space takes it from 4 nights of risk to under 1 night. 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 10/26, last around 04/16. For 20°F: 12/15 to 01/18.
How cold Washington County nights get
Average winter (Dec-Feb) low: 33°F; the coldest month, January, averages 33°F overnight. 7 months normally bring at least one night below 32°F (Jan, Feb, Mar, Apr, Oct, Nov, Dec).
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 33°F | 33°F | 36°F | 39°F | 45°F | 50°F | 54°F | 53°F | 49°F | 42°F | 37°F | 33°F |
Washington County next to its neighbours
Columbia County, OR, 43 km north, gets 7 nights below 20°F to Washington County's 4 nights. Yamhill County, OR, 38 km southwest, gets 2 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Washington County, OR | - | 60 nights | 4 nights | 33°F |
| Yamhill County, OR | 38 km southwest | 46 nights | 2 nights | 35°F |
| Columbia County, OR | 43 km north | 85 nights | 7 nights | 32°F |
| Tillamook County, OR | 53 km west | 34 nights | under 1 night | 38°F |
| Multnomah County, OR | 53 km east | 31 nights | 2 nights | 37°F |
| Clark County, WA | 53 km northeast | 71 nights | 5 nights | 32°F |
| Clatsop County, OR | 70 km northwest | 30 nights | under 1 night | 38°F |
Washington County within OR
Washington County ranks 22 of 36 OR counties for nights below 20°F. The most is Baker County, OR at 76 nights, with a 20°F average winter low. The fewest is Lincoln County, OR: under 1 night, winter lows near 40°F. At 194 ft, Washington County sits 1,823 ft below the state's median county elevation of 2,017 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.
Which pipe gets which threshold: the 32, 20, 10 and 0 rule.
Where this comes from
NOAA 1991-2020 climate normals, blended from 3 nearby stations and adjusted for elevation; closest is Forest Grove, OR, 3 km away (close match). A normal year, not tonight's forecast: check the forecast low for the night itself. What a "fair" or "distant" station match means is in the method guide.