Taking into account the local weather in Rivière-Saint-Jean can help you maximize your time at the pool during your trip. The hottest months are usually August and July with an average temp of 59°F, while the coldest months are February and January with an average of 20°F. The snowiest months in Rivière-Saint-Jean are March, February, April, and January, with each month seeing an average of 19 inches of snowfall.