Will Pipes Freeze in Custer County, SD? 98 nights a Year
Freeze nights in Custer County
In a normal year Custer County, SD gets 98 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 91% 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 | 192 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 98 nights |
| Insulated pipe in unheated space | 10°F | 44 nights |
| Inside the heated house | 0°F | 18 nights |
Foam-sleeving a bare pipe in unheated space takes it from 98 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 09/29, last around 05/15. For 20°F: 10/25 to 04/14.
How cold Custer County nights get
Average winter (Dec-Feb) low: 14°F; the coldest month, January, averages 13°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, April, October, November, December: 44 nights a year, and 18 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 13°F | 14°F | 22°F | 29°F | 39°F | 48°F | 54°F | 52°F | 43°F | 31°F | 21°F | 14°F |
Custer County next to its neighbours
Lawrence County, SD, 79 km north, gets 100 nights below 20°F to Custer County's 98 nights. Fall River County, SD, 52 km south, gets 96 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Custer County, SD | - | 192 nights | 98 nights | 13°F |
| Fall River County, SD | 52 km south | 182 nights | 96 nights | 12°F |
| Pennington County, SD | 62 km northeast | 167 nights | 83 nights | 13°F |
| Lawrence County, SD | 79 km north | 195 nights | 100 nights | 13°F |
| Oglala Lakota County, SD | 82 km southeast | 171 nights | 88 nights | 13°F |
| Weston County, WY | 91 km west | 186 nights | 102 nights | 10°F |
| Niobrara County, WY | 107 km southwest | 179 nights | 92 nights | 12°F |
Custer County within SD
Custer County ranks 29 of 66 SD counties for nights below 20°F. The most is Codington County, SD at 113 nights, with a 6°F average winter low. The fewest is Tripp County, SD: 75 nights, winter lows near 15°F. At 4,744 ft, Custer County sits 2,959 ft above the state's median county elevation of 1,785 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 Wind Cave, SD, 14 km away (fair 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.