If you're hoping to get lost in the rain on your romantic getaway, check out these details about year-round temperatures in Rocky Mountain House: The hottest months are usually August and July with an average temp of 58°F, while the coldest months are February and December with an average of 17°F. The snowiest months in Rocky Mountain House are March, February, January, and October, with each month seeing an average of 7 inches of snowfall.