Will Pipes Freeze in San Juan County, CO? 170 nights a Year
Freeze nights in San Juan County
In a normal year San Juan County, CO gets 170 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 100% of US counties.
Risk level: Severe. The risk season runs September to May, worst in January.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 268 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 170 nights |
| Insulated pipe in unheated space | 10°F | 111 nights |
| Inside the heated house | 0°F | 69 nights |
Foam-sleeving a bare pipe in unheated space takes it from 170 nights of risk to 111 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.
How cold San Juan County nights get
Average winter (Dec-Feb) low: -4°F; the coldest month, January, averages -5°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: 111 nights a year, and 69 nights below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| -5°F | -2°F | 7°F | 18°F | 26°F | 32°F | 39°F | 38°F | 31°F | 21°F | 8°F | -4°F |
San Juan County next to its neighbours
Hinsdale County, CO, 25 km east, gets 167 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| San Juan County, CO | - | 268 nights | 170 nights | -5°F |
| Hinsdale County, CO | 25 km east | 263 nights | 167 nights | -2°F |
| Ouray County, CO | 43 km north | 215 nights | 114 nights | 8°F |
| La Plata County, CO | 57 km south | 187 nights | 85 nights | 12°F |
| Mineral County, CO | 64 km southeast | 265 nights | 169 nights | -1°F |
| San Miguel County, CO | 71 km west | 210 nights | 111 nights | 7°F |
| Dolores County, CO | 74 km west | 164 nights | 70 nights | 17°F |
San Juan County within CO
San Juan County ranks 2 of 64 CO counties for nights below 20°F. The most is Summit County, CO at 177 nights, with a 5°F average winter low. The fewest is Mesa County, CO: 44 nights, winter lows near 21°F. At 9,761 ft, San Juan County sits 2,881 ft above the state's median county elevation of 6,880 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 Silverton, CO, 3 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.