May to September are the best months to visit Croatia weather-wise, though July and August can be busy along the Adriatic coast. September is probably the optimum month since by then the crowds have thinned out, off-season rates apply and fruits such as figs and grapes are abundant. In April and October it may be too cool for camping, but the weather is usually fine along the coast and private rooms are plentiful and inexpensive. You can swim in the sea from mid-June to late September.