Weather on Rugen
By German standards, Rugen enjoys an above-average number of sunshine hours and a mild yet changeable climate. In short, the weather on Rugen is quite pleasant more often than not. Average temperatures on Rugen, measured in Baabe, are as follows: January between -2 and 2°C, February between -2 and 3°C, March between 0 and 6°C, April between 4 and 12°C, May between 7 and 17°C, June between 11 and 20°C, July between 12 and 21°C, August between 12 and 21°C, September between 10 and 12°C, October between 6 and 14°C, November between 2 and 7°C, December between -1 and 4°C. 
Water Temperature on Rugen
The water temperature warms up surprisingly quickly, and we have been able to swim in the sea as early as late May! 
Sunshine Hours on Rugen
From April through September, you can expect at least 5 hours of sunshine per day — and in May, June, and July, that number rises to as many as 8 hours!