Will Pipes Freeze in Clark County, ID? 102 nights a Year
Freeze nights in Clark County
In a normal year Clark County, ID gets 102 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 92% of US counties.
Risk level: Severe. The risk season runs October to April, worst in January.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 189 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 102 nights |
| Insulated pipe in unheated space | 10°F | 44 nights |
| Inside the heated house | 0°F | 11 nights |
Foam-sleeving a bare pipe in unheated space takes it from 102 nights of risk to 44 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 09/20, last around 06/05. For 20°F: 10/23 to 04/10.
How cold Clark County nights get
Average winter (Dec-Feb) low: 13°F; the coldest month, January, averages 12°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, October, November, December: 44 nights a year, and 11 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 12°F | 14°F | 23°F | 31°F | 39°F | 45°F | 51°F | 50°F | 42°F | 31°F | 21°F | 13°F |
Clark County next to its neighbours
Jefferson County, ID, 55 km south, gets 107 nights below 20°F to Clark County's 102 nights. Madison County, ID, 79 km southeast, gets 88 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Clark County, ID | - | 189 nights | 102 nights | 12°F |
| Jefferson County, ID | 55 km south | 199 nights | 107 nights | 8°F |
| Fremont County, ID | 70 km east | 231 nights | 121 nights | 8°F |
| Madison County, ID | 79 km southeast | 186 nights | 88 nights | 12°F |
| Butte County, ID | 94 km southwest | 189 nights | 100 nights | 9°F |
| Beaverhead County, MT | 103 km northwest | 228 nights | 128 nights | 9°F |
| Teton County, ID | 109 km southeast | 208 nights | 106 nights | 9°F |
Clark County within ID
Clark County ranks 12 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 5,606 ft, Clark County sits 960 ft above 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 Small (6 mi N), ID, 4 km away (close 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.