Will Pipes Freeze in San Juan County, UT? 51 nights a Year
Freeze nights in San Juan County
In a normal year San Juan County, UT gets 51 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 65% of US counties.
Risk level: Severe. The risk season runs October to April, worst in December.
It depends where the pipe is
| Pipe | Freezes near | Nights a year |
|---|---|---|
| Outdoor spigot, open crawlspace | 32°F | 149 nights |
| Bare pipe in garage, attic or outside wall | 20°F | 51 nights |
| Insulated pipe in unheated space | 10°F | 12 nights |
| Inside the heated house | 0°F | 1 night |
Foam-sleeving a bare pipe in unheated space takes it from 51 nights of risk to 12 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 10/13, last around 05/05. For 20°F: 11/16 to 03/17.
How cold San Juan County nights get
Average winter (Dec-Feb) low: 21°F; the coldest month, January, averages 19°F overnight. 8 months normally bring at least one night below 32°F (Jan, Feb, Mar, Apr, May, Oct, Nov, Dec). Nights below 10°F, cold enough to freeze insulated pipe in an unheated space, come in January, February, November, December: 12 nights a year, and 1 night below zero.
| Jan | Feb | Mar | Apr | May | Jun | Jul | Aug | Sep | Oct | Nov | Dec |
|---|---|---|---|---|---|---|---|---|---|---|---|
| 19°F | 23°F | 29°F | 34°F | 43°F | 53°F | 59°F | 58°F | 50°F | 39°F | 28°F | 20°F |
San Juan County next to its neighbours
Montezuma County, CO, 110 km east, gets 68 nights below 20°F to San Juan County's 51 nights. Grand County, UT, 154 km north, gets 49 nights.
| County | Distance | Below 32°F | Below 20°F | Jan low |
|---|---|---|---|---|
| San Juan County, UT | - | 149 nights | 51 nights | 19°F |
| Montezuma County, CO | 110 km east | 168 nights | 68 nights | 17°F |
| Dolores County, CO | 114 km east | 164 nights | 70 nights | 17°F |
| Wayne County, UT | 128 km northwest | 138 nights | 58 nights | 18°F |
| San Miguel County, CO | 128 km east | 210 nights | 111 nights | 7°F |
| Garfield County, UT | 148 km west | 149 nights | 51 nights | 20°F |
| Grand County, UT | 154 km north | 126 nights | 49 nights | 18°F |
San Juan County within UT
San Juan County ranks 23 of 29 UT counties for nights below 20°F. The most is Rich County, UT at 138 nights, with a 6°F average winter low. The fewest is Salt Lake County, UT: 22 nights, winter lows near 28°F. At 7,197 ft, San Juan County sits 1,389 ft above the state's median county elevation of 5,807 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 Natural Bridges Nm, UT, 16 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.