In June, the weather in Janske Lazne is typically warm. Average daily high temperature in June is about 18 degrees above zero. On average, Janske Lazne has 22 rainy, 6 sunny, 1 cloudy, and 1 partly cloudy day in June. The rains are usually heavy. June as well as March, April, May, and July is considered the most uncomfortable time to visit Janske Lazne.