Our location in the country, and the world, plays a big factor in what kind of weather we see. State Climatologist Harry Hillaker says air can move unobstructed by mountains across the central United States. He explains that when arctic air from the north and warm fronts from the south meet, we see severe weather. He adds in most years the state would have already seen some form of severe weather, but it’s been too cold. Tornado season in southeast Iowa peaks in May and June.