Will Pipes Freeze in Carter County, MT? 104 nights a Year
Freeze nights in Carter County
In a normal year Carter County, MT gets 104 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 93% 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 | 184 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 104 nights |
| Insulated pipe in unheated space | 10°F | 56 nights |
| Inside the heated house | 0°F | 28 nights |
Foam-sleeving a bare pipe in unheated space takes it from 104 nights of risk to 56 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 09/22, last around 05/17. For 20°F: 10/20 to 04/15.
How cold Carter County nights get
Average winter (Dec-Feb) low: 9°F; the coldest month, January, averages 7°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: 56 nights a year, and 28 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 7°F | 11°F | 21°F | 31°F | 41°F | 51°F | 57°F | 55°F | 44°F | 32°F | 19°F | 10°F |
Carter County next to its neighbours
Bowman County, ND, 102 km northeast, gets 106 nights below 20°F to Carter County's 104 nights. Harding County, SD, 82 km east, gets 100 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Carter County, MT | - | 184 nights | 104 nights | 7°F |
| Harding County, SD | 82 km east | 183 nights | 100 nights | 8°F |
| Powder River County, MT | 82 km west | 186 nights | 97 nights | 11°F |
| Fallon County, MT | 90 km north | 185 nights | 103 nights | 7°F |
| Bowman County, ND | 102 km northeast | 189 nights | 106 nights | 7°F |
| Crook County, WY | 103 km south | 186 nights | 96 nights | 12°F |
| Butte County, SD | 105 km southeast | 177 nights | 95 nights | 10°F |
Carter County within MT
Carter County ranks 17 of 56 MT counties for nights below 20°F. The most is Sheridan County, MT at 129 nights, with a 2°F average winter low. The fewest is Lake County, MT: 40 nights, winter lows near 22°F. At 3,402 ft, Carter County sits 521 ft below the state's median county elevation of 3,922 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 Ridgeway (1 mi S), MT, 6 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.