Rovinj is one of nine settlements officially designated as towns in Istria County in western Croatia. It has a humid subtropical climate (Köppen: Cfa), with an average temperature of 4.8 °C (40.6 °F) in January and 22.3 °C (72.1 °F) in July. The average annual temperature is 13.4 °C (56.1 °F). The sea temperature is more than 20 °C (68 °F) from the mid-June to September. The average annual sea temperature is 16.6 °C (61.9 °F).
From May to September the Rovinj Croatia receives more than 10 sunshine hours a day. The rainfall averages 941 mm (37.05 in) a year and average air humidity is 72 percent.
Originally the peninsula on which the city lies was an island, separated from the mainland by a channel. The latter was filled in 1763. Rovinj Archipelago includes 22 islets.