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 14 degrees above zero. On average, Ottawa has 13 rainy, 7 sunny, 5 cloudy, and 5 partly cloudy days in April. The rains are usually heavy. April as well as February, March, November, and December is considered the most uncomfortable time to visit Ottawa.