Well Bronze .. So Cal
is kind of a large area. Can you narrow it down a bit?
In the mean time:
Santa Barbara - 20 year plus wait (if you know someone)
Ventura - still cycles okay - boat that size maybe a 3 or 4 month wait
Oxnard (Channel Islands Harbor) Small boat slips going bye bye - but there ARE some - catch it right, and no problem .. on a wait list - forget it.
Marina del Rey - If you have anything below forty feet, no one will talk with you - if you have to ask the cost - go elsewhere
King's Harbor - jammed full at that size
San Pedro - 6 month wait ... they are shifting to larger boats
Los Angeles Harbor - there is some availability and prices aren't too outrageous ... but it IS LA Harbor ..
Long Beach - Now that they've redocked everything, it's possible with about 6 month wait, but more expensive than LA, less that MdR
Alamitos Bay - only if you get lucky ... longer wait, same rate as LB (city of)
And it gets worse the further South you go.
<--- they have an online magazine called "Where the Slips Are" - it will, at least, give you places to phone
. Those places won't talk to you with any reliability
if you don't own a boat NOW and are looking for a slip NOW. Then you have to get lucky.