Planning for the weather is a good way to make your trip to Fond Du Lac relaxing and enjoyable, especially when you're splurging. The hottest months are usually July and August, with an average temperature of 14°C, while the coldest months are February and January, with an average of -20°C. The snowiest months in Fond Du Lac are January, April, December and February, with each month seeing an average of 136 cm of snowfall.