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.
From E45 take exit no. 75 to Kruså. Then onto 8 to Sønderborg and towards Augustenborg. Just before Augustenborg turn right onto 427 to Kegnaes. After Skovby drive onto a small dam, follow the street about 1km and turn left onto Bredsten, then left onto Piledøppel and get to the beach.