Will Pipes Freeze in Pennington County, SD? 83 nights a Year
Freeze nights in Pennington County
In a normal year Pennington County, SD gets 83 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 84% 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 | 167 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 83 nights |
| Insulated pipe in unheated space | 10°F | 40 nights |
| Inside the heated house | 0°F | 17 nights |
Foam-sleeving a bare pipe in unheated space takes it from 83 nights of risk to 40 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 10/01, last around 05/12. For 20°F: 10/26 to 04/09.
How cold Pennington County nights get
Average winter (Dec-Feb) low: 14°F; the coldest month, January, averages 13°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, April, October, November, December: 40 nights a year, and 17 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 13°F | 15°F | 23°F | 32°F | 42°F | 52°F | 59°F | 57°F | 47°F | 35°F | 23°F | 15°F |
Pennington County next to its neighbours
Custer County, SD, 62 km southwest, gets 98 nights below 20°F to Pennington County's 83 nights. Jackson County, SD, 103 km east, gets 79 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Pennington County, SD | - | 167 nights | 83 nights | 13°F |
| Custer County, SD | 62 km southwest | 192 nights | 98 nights | 13°F |
| Meade County, SD | 68 km north | 185 nights | 102 nights | 9°F |
| Oglala Lakota County, SD | 77 km south | 171 nights | 88 nights | 13°F |
| Lawrence County, SD | 87 km northwest | 195 nights | 100 nights | 13°F |
| Jackson County, SD | 103 km east | 158 nights | 79 nights | 13°F |
| Fall River County, SD | 103 km southwest | 182 nights | 96 nights | 12°F |
Pennington County within SD
Pennington County ranks 61 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 3,032 ft, Pennington County sits 1,247 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.
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 Rapid City Regional Airport, SD, 19 km away (close 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.