Weather is probably a major factor when you plan your trip to Le Grand-Bornand, and keep in mind that cheaper options are usually available when the weather isn't as good. The hottest months are usually July and August with an average temp of 58°F, while the coldest months are January and February with an average of 29°F. The snowiest months in Le Grand-Bornand are October, September, May, and December, with each month seeing an average of 5 inches of snowfall.