Hi Rick,
Not really sure what you're looking for, because there are of course customs and culture that are common to virtually the whole of Spain, and which you can really only find out about by actually living there.
If you're referring to culture and customs particular to Cádiz, then I suggest you do some research on the following :-
- Chirigotas (music)
- Fino (drink)
- Horse racing on the beach in Sanlúcar (in August)
- Gambas de Sanlúcar (shrimps famous all over Spain -- expensive but good!)
Unfortunately you'll be arriving late for the Carnival, which is famous in Cádiz, but in time for the "Feria de Sevilla" in case you can make it across to that splendid city for a visit.
Have fun and please don't forget to report back with your first impressions of Cádiz in particular and Andalusia and Spain in general!
Roger.