The best time of year to go to Croatia is from June through September which is best for people that are sun seekers or beach goers.
The months of June through September in Croatia has warm weather and lively festivals although there are also higher prices and also crowds.
If you want to visit Croatia but avoid the crowds and avoid the heat, then the shoulder months of May and October are the best best months to go to Croatia and is great for going sightseeing and for visiting of national parts.
Winter can also be a good option for a time of year for going to Croatia as there are Christmas markets in Zagreb as well as skiing in the Croatia mountains.
Although during the winter most coastal resorts in Croatia close.
Summer from June through September in Croatia has the warmest weather and is great for beach holidays, swimming and also for exploring the beautiful Adriatic coast and the islands and there also many cultural events and festivals.
Although the summer months is peak tourist season in Croatia so you should expect large crowds and higher prices for flights and accommodation.
The shoulder seasons of Croatia which are May & October have a good balance of pleasant weather and smaller crowds, which is also great for exploring the national parks in Croatia such as Krka and Plitvice and many of the attractions are still open, and you can also enjoy leisurely pace.
Although the sea in Croatia during the shoulder seasons may also be a bit too cool for swimming in May and by the month of October, some restaurants in Croatia as well as some accommodations may begin to close for winter.