If you're looking forward to lots of outings with your partner, take a look at these details about year-round temperatures in Bonnyville: The hottest months are usually July and August, with an average temperature of 15°C, while the coldest months are February and January, with an average of -11°C. The snowiest months in Bonnyville are February, April, January and March, with each month seeing an average of 44 cm of snowfall.