May in Smithers is the rainiest month of the year. In May, the weather in Smithers is typically cold. Average daily high temperature in May is about 9 degrees above zero. On average, Smithers has 24 rainy, 4 cloudy, 2 sunny, and 1 partly cloudy day in May. The rains are usually moderate. May as well as April, June, September, and October is considered the most uncomfortable time to visit Smithers.