Why heat is so deadly and how to stay safe

Extreme heat kills more people in the U.S. than any other weather disaster, and heat waves are getting hotter and more frequent as the climate warms. Humidity makes things worse: when heat and humidity combine into a high "wet bulb temperature" (a measure of how well sweat can still cool you), your body loses its ability to cool itself, sometimes leading to heat exhaustion or heatstroke. Nighttime temperatures are rising even faster than daytime ones in many places, cutting into the cooling-off period your body and house both need overnight.

Your house plays a real role in how much danger you're in during a heat wave. Sealing gaps around windows and doors keeps hot air out, dehumidifying indoor air helps your body cool more effectively, and covering windows with blackout shades or blinds blocks the sun from heating rooms up. In dry climates, some people build simple do-it-yourself air conditioning setups. Keeping water, electrolytes, and ice on hand, and knowing a cool public space like a library, matters too, since heat waves can strain the power grid and cause outages just when you need cooling most.

For longer-term protection, home upgrades like reflective roofing, window overhangs that block direct sun, and better insulation can meaningfully cut indoor heat. These changes work alongside the everyday steps of sealing and shading, giving a house more lasting resistance to extreme heat rather than just short-term relief during a single wave.