Kraljevica is at its most pleasant in June and September, when the Kvarner coast is warm and sunny but not overwhelmed by summer crowds. The town sees far fewer tourists than Opatija or Crikvenica, so even July and August remain relatively relaxed compared to the busier resorts. Swimming is good from June through to early October; water temperatures in the Kvarner Gulf peak around 24–26°C in August.
Winter is mild by northern European standards — Rijeka is one of the cloudiest cities in Croatia, and Kraljevica shares some of that tendency for winter rain and bura wind — but the castles and waterfront are accessible year-round. Most restaurants and cafes stay open through the year, as the town has a resident population rather than relying entirely on summer visitors.
The Kvarner Gulf is prone to the bura, a strong cold northeasterly wind that can arrive suddenly in autumn and winter. It rarely causes problems for sightseeing in town, but can make the sea rough and affect ferries to Krk.