In another sign California's persistent drought, downtown San Francisco recorded no measurable rain in January for the first time in 165 years.
The National Weather Service also said Santa Cruz recorded no rain in January for the first time since 1893. Normal rainfall for that city in January is more than 6 inches.
For the Bay Area as a whole, last month was the driest January on record, the weather service said.
December brought decent rain to Southern and Northern California, raising hopes for a wet winter. But January turned out to be dry and unusually warm.