Weather can make or break a roadtrip, so here's some data about year-round temperatures in Rocanville to help you plan yours: The hottest months are usually July and August with an average temp of 62°F, while the coldest months are February and January with an average of 12°F. The snowiest months in Rocanville are February, December, January, and March, with each month seeing an average of 19 inches of snowfall.