April in Green Bay is the rainiest month of the year. In April, the weather in Green Bay is typically cold. Average daily high temperature in April is about 9 degrees above zero. On average, Green Bay has 11 rainy, 10 cloudy, 5 sunny, and 4 partly cloudy days in April. The rains are usually moderate. April as well as March and November is considered the most uncomfortable time to visit Green Bay.