The Costa Blanca is well known for a Mediterranean climate with mild winters and hot dry summers. In winter the average temperature is about 20 degrees Celsius, and it's usually not colder than 4 or 5 degrees. During summertime average temperature is around 30 degrees. Regarding the little breeze that flows daily from the sea it's usually comfortable enough to stay outside, even with very high temperatures. 
Click at the link to find the average temperatures, Rainfall per month, sunhours per day, watertemperature of the Mediterranean, and more.