Visiting local bars in Rideau Lakes is better when the weather is good. These rainfall averages and temperatures can help you determine the best time for bar-hopping. The hottest months are usually July and August, with an average temperature of 19°C, while the coldest months are January and February, with an average of -4°C. The snowiest months in Rideau Lakes are January, February, December and November, with each month seeing an average of 45 cm of snowfall.