The suitable time to visit Plitvice Lakes National Park is during the spring (April to June) or autumn (September to October). The park is less crowded in these months, and the waterfalls are at their fullest due to rainfall. In spring, the park is lush and green, while autumn offers stunning foliage. The summer months can be very crowded, especially in July and August, while winter transforms the park into a snowy wonderland, though some areas may be inaccessible. The park is open year-round, but spring and autumn provide the best balance of beauty, accessibility, and fewer tourists.