Planning for the weather is a good way to make your trip to Kemptville relaxing and enjoyable, especially when you’re splurging. The hottest months are usually August and July with an average temp of 61°F, while the coldest months are February and January with an average of 34°F. The snowiest months in Kemptville are January, February, March, and April, with each month seeing an average of 10 inches of snowfall.