Viana do Castelo is a great spot for every discipline and level of rider. At Cabedelo you have flat water and further south you have waves, good ones. There are kitesurfing and surfing centers rigth at the beach. Even tough the summer is quite warm, water is a bit on the cold side (~17ºC), a 4/3mm is recommended in the summer.
The wind is north, right riding to hit the kickers. The best wind is typically in the summer afternoons, with wind frequently going over 20 knots. In the summer you will have a high chance of getting wind in the afternoon, the winter is less frequent and more unpredictable.
The beach may be a bit crowded, but this is solved when the wind picks up or the tide is low and you have more space for setting up. On the flat water side there are usually more kiters and windsurfers, further south you will have plenty of space.
The all region is very rich in culture and good food, with a lot to do if the wind does not blow. Perfect for family and very safe.
Perfect for beginners and advanced riders.