Dear Tom,

What is more dangerous, heat waves or intense cold spells?

—Fred Brinbaum, Elmhurst

Dear Fred,

The number of deaths from any given weather hazard varies from year to year, but year in and year out intense summer heat is the nation’s leading weather killer. It is an underrated and often overlooked silent killer. And when high humidity accompanies extreme heat, the deadly nature of multi-day heat waves is greatly magnified. A four-day siege of stifling heat and humidity in mid July, 1995, claimed more than 700 lives in Chicago, the city’s worst-ever killer weather event. Six weather events are the nation’s leading weather killers: The average annual toll from hurricanes is 25; from tornadoes, 73; lightning, 85; from winter cold, 126; from floods, 136; from summer heat waves, 500.