Choppy with little waves. The waves can get very nice, with strong SSE to SE winds north of the mole. With stronger North winds nice waves south of the mole. Keep distance from the mole and watch the boats.
Small sandy beach. Not much space. Be careful when launching and landing. If you want to start south from the mole be careful, since the street is directly next to the beach.
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 exit Kruså (Nr. 75). Then onto 8 to Sønderborg and towards Augustenborg. Just before Augustenborg turn right towards Kegnaes. After a few kilometers turn left towards Mommark. The beach is just at the end of the street at the small harbor. Either south or north of the harbor, depending on the wind direction.