Between 16 to 20 deg in the day, you will get a mixture of rain, cloudy and sunny days, at night it goes cold, down to 10 deg so don't get caught out with just your shorts and tee shirt on when the sun goes down. But a great place to be whatever the weather, enjoy.
I was in Costa Blanca, golfing, last month and came back with a tan. 1 rainy day, 2 overcast and the rest glorious sun and average temp of 15-16deg. Cold at night though. Unsure how much of a difference there is between the Costa's?