The coast is swimmable from May to October, with July and August being the hottest and most crowded months. June and September are the best compromise — warm enough for the sea, quieter, cheaper.
The Croatia Open ATP tennis tournament takes place in the last week of July. If you want to watch world-class clay-court tennis in an intimate setting, this is a rare opportunity: the main stadium holds only a few thousand spectators. Book accommodation well in advance for tournament week.
Winters are mild by northern European standards but the town is very quiet. Most restaurants and bars outside the old town close from November to March.