Mid-July is usually one of the hottest times of the year in South Dakota. But with lows in the 40s and highs in the 60s in much of the state, it feels more like fall. Although some are referring to the unseasonably chilly air as a return of the polar vortex, it’s not. Climatologists and meteorologists say it’s simply a cooler than normal Canadian air mass hitting the region. South Dakota. State climatologist Dennis Todey joined Dakota Midday and discussed what’s causing the cool temperatures and what their impact could be.