Weather can make or break a road trip, so here's some data about year-round temperatures in Heihe to help you plan yours: The hottest months are usually July and August, with an average temperature of 18°C, while the coldest months are January and December, with an average of -17°C. The snowiest months in Heihe are January, February, December and November, with each month seeing an average of 58 cm of snowfall.