There are usually quite a few people on the Brioni Beach from September to May.
From June to September the air temperature at Brioni Beach is perfect for sunbathing. The swimming season at Brioni Beach occurs from July to September, when the water is warm and comfortable for swimming.
In December, in June and in November and October Brioni Beach has rainy season. This is something to keep in mind when planning your trip since it is quite possible that you may be unable to sunbathe.