If you're hoping to get lost in the rain on your romantic getaway, take a look at these details about year-round temperatures in Hillman: The hottest months are usually July and August, with an average temperature of 18°C, while the coldest months are February and January, with an average of -4°C. The snowiest months in Hillman are January, February, December and March, with each month seeing an average of 27 cm of snowfall.