The season goes from April to November. In that time air from spring 10-20°C, in summer up to 30°C and autumn 10-16°C. Water spring 8-13°C, summer 18-23°C, autumn 8-14°C. You always need a wetsuit. You can go out off-season but it will be very cold, a thick wetsuit or better drysuit, mask, shoes and gloves recommended.
Go to Denmark. Drive to Ringkobing. The spot is 500m south of the camping area and windsurf club, just outside the town. Turn left after passing town sign into the parking area.