Will Pipes Freeze in Washington County, ID? 55 nights a Year
Freeze nights in Washington County
In a normal year Washington County, ID gets 55 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 68% of US counties.
Risk level: Severe. The risk season runs October to March, worst in January.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 154 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 55 nights |
| Insulated pipe in unheated space | 10°F | 20 nights |
| Inside the heated house | 0°F | 6 nights |
Foam-sleeving a bare pipe in unheated space takes it from 55 nights of risk to 20 nights. 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 09/27, last around 05/15. For 20°F: 11/01 to 03/17.
How cold Washington County nights get
Average winter (Dec-Feb) low: 20°F; the coldest month, January, averages 18°F overnight. 9 months normally bring at least one night below 32°F (Jan, Feb, Mar, Apr, May, Sep, Oct, Nov, Dec). Nights below 10°F, cold enough to freeze insulated pipe in an unheated space, come in January, February, March, November, December: 20 nights a year, and 6 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 18°F | 22°F | 30°F | 36°F | 43°F | 50°F | 57°F | 55°F | 45°F | 35°F | 27°F | 20°F |
Washington County next to its neighbours
Adams County, ID, 55 km northeast, gets 109 nights below 20°F to Washington County's 55 nights. Payette County, ID, 50 km south, gets 35 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Washington County, ID | - | 154 nights | 55 nights | 18°F |
| Payette County, ID | 50 km south | 138 nights | 35 nights | 23°F |
| Gem County, ID | 53 km southeast | 157 nights | 51 nights | 20°F |
| Adams County, ID | 55 km northeast | 230 nights | 109 nights | 11°F |
| Baker County, OR | 76 km west | 202 nights | 76 nights | 19°F |
| Canyon County, ID | 92 km south | 117 nights | 27 nights | 24°F |
| Boise County, ID | 100 km southeast | 238 nights | 101 nights | 12°F |
Washington County within ID
Washington County ranks 30 of 44 ID counties for nights below 20°F. The most is Custer County, ID at 145 nights, with a 5°F average winter low. The fewest is Nez Perce County, ID: 20 nights, winter lows near 27°F. At 2,995 ft, Washington County sits 1,651 ft below the state's median county elevation of 4,646 ft.
What to do here
- Treat it as a building fix, not a night-of routine: insulate, heat tape, seal crawlspace vents.
- An automatic leak shutoff pays for itself if one burst is avoided.
- Know where the main shutoff is before the first hard freeze.
Interior pipes have a threshold too: the four freeze points.
Where this comes from
NOAA 1991-2020 climate normals, blended from 3 nearby stations and adjusted for elevation; closest is Cambridge, ID, 17 km away (fair match). A normal year, not tonight's forecast: check the forecast low for the night itself. How a county figure is built from stations: how the numbers are made.