April in Winona is the rainiest month of the year. In April, the weather in Winona is typically warm. Average daily high temperature in April is about 11 degrees above zero. On average, Winona has 18 rainy, 5 sunny, 4 cloudy, and 3 partly cloudy days in April. The rains are usually heavy. April as well as March is considered the most uncomfortable time to visit Winona.