Weather can make or break a roadtrip, so we've gathered some data about year-round temperatures in Elgin to help you plan yours. The hottest months are usually July and August with an average temp of 69°F, while the coldest months are January and February with an average of 23°F. The snowiest months in Elgin are April, March, October, and February, with each month seeing an average of 9 inches of snowfall.