Ice dam risk in San Francisco, CA
How often ice dams form in San Francisco
0.0 dam days a winter
Almost never. An ordinary house in San Francisco sees 0.0 days a winter when an ice dam can form, because snow rarely stays on a roof long enough below freezing.
San Francisco averages 0 inches of snow a year and about 0 days with snow on the ground. Too little lies on the roof for long. The conditions that make a dam need all three at once: snow, cold at the eave and heat above it.
Do you need to do anything in San Francisco?
- Nothing for ice dams. If you are buying here and an inspector mentions water at the eaves, ask what they saw: it is far more likely a gutter, flashing or drip-edge problem than ice.
Snowy places are not always the worst: why snowfall misleads.
San Francisco next to nearby towns
San Francisco ranks 9 of 376 California cities here for ice-dam days, behind Truckee at 36.3 days.
- Mill Valley, CA 30 mi, 0.0 days
- San Anselmo, CA 31 mi, 0.0 days
- Daly City, CA 31 mi, 0.0 days
- Larkspur, CA 31 mi, 0.0 days
- Pacifica, CA 31 mi, 0.0 days
Where these numbers come from
NOAA 1991–2020 climate normals from San Francisco Oceanside, 28.8 miles from San Francisco. A dam day is a day with snow on the roof and freezing at the eave while heat or sun melts the snow above it. This describes a normal winter, not this one.
- The weather station is 29 miles away, far enough that local snow can differ.