Will Pipes Freeze in Silver Bow County, MT? 127 nights a Year
Freeze nights in Silver Bow County
In a normal year Silver Bow County, MT gets 127 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 December.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 235 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 127 nights |
| Insulated pipe in unheated space | 10°F | 66 nights |
| Inside the heated house | 0°F | 29 nights |
Foam-sleeving a bare pipe in unheated space takes it from 127 nights of risk to 66 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 09/05, last around 06/13. For 20°F: 10/12 to 04/26.
How cold Silver Bow County nights get
Average winter (Dec-Feb) low: 9°F; the coldest month, December, averages 7°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: 66 nights a year, and 29 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 9°F | 10°F | 18°F | 25°F | 33°F | 40°F | 44°F | 42°F | 35°F | 26°F | 16°F | 7°F |
Silver Bow County next to its neighbours
Deer Lodge County, MT, 43 km northwest, gets 113 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Silver Bow County, MT | - | 235 nights | 127 nights | 9°F |
| Deer Lodge County, MT | 43 km northwest | 230 nights | 113 nights | 13°F |
| Jefferson County, MT | 53 km northeast | 214 nights | 107 nights | 10°F |
| Granite County, MT | 81 km northwest | 215 nights | 98 nights | 15°F |
| Madison County, MT | 86 km southeast | 213 nights | 107 nights | 13°F |
| Beaverhead County, MT | 87 km south | 228 nights | 128 nights | 9°F |
| Broadwater County, MT | 102 km northeast | 174 nights | 83 nights | 14°F |
Silver Bow County within MT
Silver Bow County ranks 4 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 5,815 ft, Silver Bow County sits 1,892 ft above 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.
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 Butte Bert Mooney Airport, MT, 15 km away (close match). A normal year, not tonight's forecast: check the forecast low for the night itself. What a "fair" or "distant" station match means is in the method guide.