Hi eutanator, here is the information:
Medium temperature in August is around 25 C.
Medium temparature in September is around 20 C.
Wind speed: in the past few weeks the wind has been blowing around 3 times per week. In september chances are better that you will have good wind, but you can never know. Mostly you will need a big kite, 16m.
KITE BEACH: 95% of hungarian kiters go to the beaches between Szabadi-furdo and Szabadi-Sosto. This is on the southern shore of the lake; do not even consider kiting on the north shore!
I am there every weekend. If you need additional information you can also mail me under: firstname.lastname@example.org