May in Tornio is the rainiest month of the year. In May, the weather in Tornio is typically warm. Average daily high temperature in May is about 10 degrees above zero. On average, Tornio has 15 rainy, 7 partly cloudy, 6 sunny, and 3 cloudy days in May. The rains are usually moderate. May as well as April, September, October, and November is considered the most uncomfortable time to visit Tornio.