Joniskis, Lithuania offers 2 beaches perfect for sunbathing, surfing, swimming, and more. Joniskis, known for the Joniskis Basketball Museum and the historic Joniskis Synagogue Complex. Utena, famous for the Aukstaitija National Park and the Utena Brewery. Lithuania, renowned for the Hill of Crosses and the Curonian Spit. The best time to travel to Joniskis, Lithuania, is during the summer months of June to August, when the average air temperature is around 17-20°C (63-68°F) and water temperature is approximately 18-22°C (64-72°F). Sandee provides detailed maps, photos, and reviews from fellow beachgoers to help you Choose Your Beach™ and plan your perfect beach vacation!