Here a summary of my 2 weeks stay at Riu Tres Islas near Corralejo and kitesurfing spot at Flagbeach.
First constant sunshine and affordable heat (24-30°) which is pretty normal in July.
Hotel Riu, directly situated at the beach, is clean and comfortable with an everyday changing buffet (no full board possibility however small buffet at lunch as an extra). Half of the personnel is only Spanish speaking, however they are servable and available.
Beach is huge, water very clean and in some places wavy but accessible to swimmers and children.
Kite school and rental club 'Flagbeach' is well equipped for kitesurfing and windsurfing, team and instructors are international, professional, always friendly and ready to advise or assist you.
Spot itself, with waves (1.5m) and rocks at low tide, is rather for confirmed and expert kite surfers. By onshore or low wind condition, a daily shuttle is organized to El Cottilo spot (at opposite north west coast) for a launch from a boat and downwind sessions, an enjoyable experience that I recommend to beginners and confirmed.