Summer in the south of Spain is very hot (July and August are the worst months), and most people who like sunny weather without extreme heat prefer to visit in May, June, or September. 

Oye china, vete a Canarias, hay siempre sol y aprenderas Español en la playa. Ciao

I live in the north of Spain, Galicia, and there is not always raining. In summer the weather is cooler but the sun shines. Last summer I could go to the beach many days. In addition, we have wonderful beaches.

I was in Madrid in the Summer, June-August season and the weather was great. When I traveled to some of the cities in the North, it was a bit cold and rainy but in general I enjoyed the weather during those months. :) I hope that helps. Have a great trip. :D

It depends which part you are going to be in. The north is usually rainy and colder, even in summer. However in Madrid summers are very sunny like in the south part