In April, the weather in Niagara Falls is typically warm. Average daily high temperature in April is about 11 degrees above zero. On average, Niagara Falls has 14 rainy, 7 cloudy, 6 sunny, and 3 partly cloudy days in April. The rains are usually heavy. April as well as March, October, November, and December is considered the most uncomfortable time to visit Niagara Falls.