May weather forecast in Saint John

May in Saint John is the rainiest month of the year. In May, the weather in Saint John is typically warm. Average daily high temperature in May is about 12 degrees above zero. On average, Saint John has 14 rainy, 11 cloudy, 4 sunny, and 2 partly cloudy days in May. The rains are usually heavy. May as well as March, April, October, and November is considered the most uncomfortable time to visit Saint John.