Yes, but not the whole state. Only the blue areas of California should be allowed to go, minus any federal land (like national parks) within those areas.
I would suggest LA ns San Francisco and then everything from the San Andrea Fault west
Partition an area with approximately a coastal range of hills as the eastern boundary, defining the San Francisco and Los Angeles urban areas as the northern and southern extent. Allow any less urban regions that reside in between to make their own choice.
San Diego region south of the Dana point to Coachella line is excluded from this partition. The region north of the Sacramento River and it’s outlet is excluded. The areas beyond the eastern hills boundary will sort out reformed State of California issues.
The seceded coastal area will decide on a new identity for themselves. Thereafter they will have to find a source of water to replace that which is no longer allocated from the inland basins within the continental United States (Pacific Ocean desalination a possibility).