Will Pipes Freeze in Mono County, CA? 130 nights a Year
Freeze nights in Mono County
In a normal year Mono County, CA gets 130 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 June, worst in December.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 255 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 130 nights |
| Insulated pipe in unheated space | 10°F | 55 nights |
| Inside the heated house | 0°F | 18 nights |
Foam-sleeving a bare pipe in unheated space takes it from 130 nights of risk to 55 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 09/17, last around 06/10. For 20°F: 10/24 to 04/26.
How cold Mono County nights get
Average winter (Dec-Feb) low: 13°F; the coldest month, January, averages 13°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: 55 nights a year, and 18 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 13°F | 14°F | 18°F | 23°F | 30°F | 37°F | 42°F | 41°F | 34°F | 26°F | 19°F | 13°F |
Mono County next to its neighbours
Mineral County, NV, 78 km northeast, gets 28 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| Mono County, CA | - | 255 nights | 130 nights | 13°F |
| Mineral County, NV | 78 km northeast | 115 nights | 28 nights | 26°F |
| Tuolumne County, CA | 96 km west | 91 nights | 11 nights | 31°F |
| Mariposa County, CA | 99 km west | 94 nights | 5 nights | 31°F |
| Madera County, CA | 110 km southwest | 41 nights | 1 night | 36°F |
| Esmeralda County, NV | 110 km east | 136 nights | 54 nights | 19°F |
| Alpine County, CA | 113 km northwest | 189 nights | 58 nights | 22°F |
Mono County within CA
Mono County ranks 1 of 58 CA counties for nights below 20°F. The fewest is Orange County, CA: none, winter lows near 46°F. At 8,067 ft, Mono County sits 6,769 ft above the state's median county elevation of 1,298 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 Mammoth Lakes Ranger Station, CA, 31 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.