Croatia has a varied climate, with continental climate conditions in the north and Mediterranean ones on the Adriatic coast.
Required clothing: Lightweights with rainwear for summer. Mediumweights for winter with heavier clothing for inland areas.

Climate for the Adriatic coast:

The warmest months are July and August when the air temperature is between 25° C and 35° C ( 77° F - 95° F) and the sea temperature reaches up to 28° C (83° F). The rain is very rare. This is the time when most of the tourists come.

If you';re for a quieter time at the beach and not so many tourists, maybe June and September are months for you. They are also very warm months with average temperatures around 25° C (77° F) and the sea surface temps between 20° C and 25° C ( 68° F - 77° F).

Sunbathing and swimming is also possible in April, May and October, but it really depends on the weather and chances are that you'll get more sunshine in the southern Adriatic. In that period expect temperature between 15° C and 25° C ( 59° F - 77° F) and the sea temperature between 16 and 21° C (61 - 70° F). This is a period with more rain and windy days.

The air temperature in winter months is between 5 and 10° C (41-50° F) and the sea temperature is in average 12 ° C (54 ° C ).