Will Pipes Freeze in Flathead County, MT? 63 nights a Year
Freeze nights in Flathead County
In a normal year Flathead County, MT gets 63 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 73% 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 | 178 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 63 nights |
| Insulated pipe in unheated space | 10°F | 26 nights |
| Inside the heated house | 0°F | 9 nights |
Foam-sleeving a bare pipe in unheated space takes it from 63 nights of risk to 26 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 05/09. For 20°F: 11/07 to 03/31.
How cold Flathead County nights get
Average winter (Dec-Feb) low: 19°F; the coldest month, January, averages 18°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, October, November, December: 26 nights a year, and 9 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 18°F | 19°F | 25°F | 32°F | 40°F | 46°F | 51°F | 49°F | 41°F | 32°F | 26°F | 20°F |
Flathead County next to its neighbours
Glacier County, MT, 91 km northeast, gets 85 nights below 20°F to Flathead County's 63 nights. Lake County, MT, 73 km south, gets 40 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Flathead County, MT | - | 178 nights | 63 nights | 18°F |
| Lake County, MT | 73 km south | 145 nights | 40 nights | 22°F |
| Glacier County, MT | 91 km northeast | 189 nights | 85 nights | 13°F |
| Sanders County, MT | 103 km southwest | 212 nights | 81 nights | 18°F |
| Lincoln County, MT | 108 km west | 193 nights | 61 nights | 19°F |
| Pondera County, MT | 136 km east | 173 nights | 82 nights | 13°F |
| Missoula County, MT | 142 km south | 189 nights | 72 nights | 16°F |
Flathead County within MT
Flathead County ranks 53 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 6,673 ft, Flathead County sits 2,750 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.
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 Hungry Horse Dam, MT, 6 km away (distant 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.