The new hours are a far cry from several years ago when budget cuts forced some branches to open only part time.
Cecilia Ortega is a teacher who's spending her summer at the library with her son Emiliano.
"He's already gained a lot of language through books. That's one of the few times he'll sit still because he has so much energy," Ortega said.
Now all public library branches in San Francisco will be open every day, adding 17 librarians and staff.
Nine branches will add an extra day, and 15 branches will extend their hours, costing tax payers an additional $1.8 million.
A parcel tax and bond measure passed a few years ago made it clear that libraries should be an essential service in San Francisco.
"We were fortunate to have so many residents and voters vote for their library to make sure they're seismically safe, they are expanded, they are modernized," San Francisco Mayor Ed Lee said.
It wasn't that long ago that budget cuts forced some libraries to open only a few days a week. But thanks to the library preservation fund and friends of the library they have now become more like community centers, offering art classes and access to computers for those who want to earn their high school diploma.
"Each and every one of our 27 neighborhood libraries has a variety of programs and good collection and resources," librarian Luis Herrera said.
The hours at each branch range from 50 to 60 hours a week.
To find out when the library in San Francisco near you is open, click here.