Some, but not all, bishops in California are canceling Masses.

Masses not cancelled in San Francisco archdiocese
Masses not cancelled in LA archdiocese
Not cancelled in Orange diocese
Not cancelled in Oakland, with partial exception for Contra Costa County.
Bishop Soto has decreed broad dispensation in Sacramento, but “Pastors are to continue offering Sunday Mass for those members of faithful who desire and are able to attend.”
From Bishop Barnes in San Bernardino: “We will continue to hold Masses in our parishes as scheduled.”
Masses are cancelled in San Diego
Masses suspended in San Jose
Dispensation granted but (apparently) Masses not cancelled in Stockton diocese.
Santa Rosa Bishop Robert Vasa issues dispensation but does not cancel Masses, provides detailed instructions to priests/parishes.
Fresno: All daily and weekend Masses will be suspended as of Monday, March 16 through Sunday, March 29, 2020. (Policy updated weekly.)