If you’re looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Stateline: The hottest months are usually July and August, with an average temperature of 15°C, while the coldest months are February and December, with an average of -2°C. The snowiest months in Stateline are March, February, January and December, with each month seeing an average of 75 cm of snowfall.