In April, the weather in Flachau is typically cold. Average daily high temperature in April is about 10 degrees above zero. On average, Flachau has 11 rainy, 7 sunny, 7 partly cloudy, 4 cloudy, and 1 snowy day in April. The rains are usually heavy. April as well as March, May, June, and July is considered the most uncomfortable time to visit Flachau.