Spring: air 14°C, water 12°C. Summer: air 20°C, water 16°C. Fall: air 12°C, water 12°C. Winter: air 4°C, water 8°C. Season is year round in principal, but May to October is the best. Wetsuit is necessary, especially in spring and autumn. Winter can be really cold. In summer a shorty is sufficient.
Extremely hazardous spot, big currents, no rescue services, big waves, sandy banks and riptides. If you are a very good kite/windsurfer/surfer and you can pay the 200 Euro an hour for a rescue boat stand-by its worth it. Ask locals for more information.