Weather can make or break a roadtrip, so we've gathered some data about year-round temperatures in Big Bear City to help you plan yours. The hottest months are usually July and August with an average temp of 73°F, while the coldest months are February and December with an average of 46°F. The snowiest months in Big Bear City are February, March, January, and May, with each month seeing an average of 10 inches of snowfall.