Weather can make or break a roadtrip, so we've gathered some data about year-round temperatures in Granger 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 January and February with an average of 32°F. The snowiest months in Granger are January, December, November, and February, with each month seeing an average of 6 inches of snowfall.