Will Pipes Freeze in Custer County, ID? 145 nights a Year
Freeze nights in Custer County
In a normal year Custer County, ID gets 145 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 99% of US counties.
Risk level: Severe. The risk season runs September to May, worst in January.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 261 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 145 nights |
| Insulated pipe in unheated space | 10°F | 83 nights |
| Inside the heated house | 0°F | 43 nights |
Foam-sleeving a bare pipe in unheated space takes it from 145 nights of risk to 83 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 09/08, last around 06/14. For 20°F: 10/16 to 04/24.
How cold Custer County nights get
Average winter (Dec-Feb) low: 5°F; the coldest month, January, averages 3°F overnight. 12 months normally bring at least one night below 32°F (Jan, Feb, Mar, Apr, May, Jun, Jul, Aug, Sep, Oct, Nov, Dec). Nights below 10°F, cold enough to freeze insulated pipe in an unheated space, come in January, February, March, April, October, November, December: 83 nights a year, and 43 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 3°F | 6°F | 15°F | 23°F | 30°F | 36°F | 40°F | 38°F | 31°F | 24°F | 14°F | 5°F |
Custer County next to its neighbours
Lemhi County, ID, 78 km north, gets 135 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Custer County, ID | - | 261 nights | 145 nights | 3°F |
| Lemhi County, ID | 78 km north | 239 nights | 135 nights | 7°F |
| Camas County, ID | 95 km southwest | 233 nights | 126 nights | 8°F |
| Blaine County, ID | 101 km south | 193 nights | 101 nights | 9°F |
| Butte County, ID | 108 km southeast | 189 nights | 100 nights | 9°F |
| Boise County, ID | 121 km west | 238 nights | 101 nights | 12°F |
| Valley County, ID | 126 km northwest | 252 nights | 117 nights | 9°F |
Custer County within ID
Custer County ranks 1 of 44 ID counties for nights below 20°F. The fewest is Nez Perce County, ID: 20 nights, winter lows near 27°F. At 7,395 ft, Custer County sits 2,749 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.
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 Chilly Barton Flat, ID, 47 km away (distant 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.