> Costa Blanca
This area is mostly single pitch limestone sport climbing, and has at least 8 crags with a few hundred routes. See the rockfax climbing costa blanca guide for english info. Probably good climbing temperatures October-April, even in December it could be too hot in the sun.
A car is probably necessary to get to all the different crags. The area is easily accessible from Calpe, where you can find good accomodation. We flew into Valencia airport and rented a car from there, but you can also fly to Alicante airport which is bigger.