Summer is nice and warm. High season a short is ok, a few weeks with just shorts is possible. Usually a wetsuit is always needed. Water max 22°C in summer, normally around 15°C. Winter gets cold, but a thick wetsuit, gloves, mask and shoes make kiting almost year-round possible. Air: summer between 20-30°C, spring and fall around 15°C.
Take A28 and A31 to Emden. Exit at Emden-Nord onto B210 and Georgsheil turn left onto B72 direction Norden. In Norden towards Norddeich. Now you need to take a ferry for about 45min. On Norderney you can take your car to this beach. Drive to the East and just before the golf course turn left towards Weisse Duene. Free parking behind the dunes. You need to walk for about 500m to get to the water. Special rules for using your car during the season. Check the internet before you go.