Will Pipes Freeze in Lewis County, ID? 40 nights a Year
Freeze nights in Lewis County
In a normal year Lewis County, ID gets 40 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 56% of US counties.
Risk level: Severe. The risk season runs October to April, worst in December.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 159 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 40 nights |
| Insulated pipe in unheated space | 10°F | 11 nights |
| Inside the heated house | 0°F | 3 nights |
Foam-sleeving a bare pipe in unheated space takes it from 40 nights of risk to 11 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 09/25, last around 05/23. For 20°F: 11/08 to 03/21.
How cold Lewis County nights get
Average winter (Dec-Feb) low: 23°F; the coldest month, December, averages 22°F overnight. 10 months normally bring at least one night below 32°F (Jan, Feb, Mar, Apr, May, Jun, 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: 11 nights a year, and 3 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 23°F | 24°F | 28°F | 33°F | 40°F | 45°F | 50°F | 50°F | 44°F | 35°F | 28°F | 22°F |
Lewis County next to its neighbours
Asotin County, WA, 62 km west, gets 52 nights below 20°F to Lewis County's 40 nights. Nez Perce County, ID, 28 km northwest, gets 20 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Lewis County, ID | - | 159 nights | 40 nights | 23°F |
| Nez Perce County, ID | 28 km northwest | 109 nights | 20 nights | 27°F |
| Asotin County, WA | 62 km west | 179 nights | 52 nights | 20°F |
| Latah County, ID | 69 km north | 143 nights | 29 nights | 25°F |
| Clearwater County, ID | 76 km northeast | 209 nights | 55 nights | 19°F |
| Idaho County, ID | 85 km southeast | 243 nights | 94 nights | 15°F |
| Garfield County, WA | 88 km west | 125 nights | 25 nights | 27°F |
Lewis County within ID
Lewis County ranks 37 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 3,659 ft, Lewis County sits 987 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.
At this many nights, foam alone is not the answer: insulate or heat tape?.
Where this comes from
NOAA 1991-2020 climate normals, blended from 3 nearby stations and adjusted for elevation; closest is Winchester, ID, 15 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.