April in Ottawa is the windiest month of the year. In April, the weather in Ottawa is typically warm. Average daily high temperature in April is about 16 degrees above zero. On average, Ottawa has 12 rainy, 9 sunny, 6 partly cloudy, and 3 cloudy days in April. The rains are usually heavy. April as well as January, February, March, and November is considered the most uncomfortable time to visit Ottawa.