Extreme Weather: Before, During, and After

Extreme temperatures, both heat and cold, kill more people every year than most other natural disasters combined, often without anyone noticing until it's too late. They hit cities on every continent: prolonged heatwaves in summer and severe cold fronts in winter, both of which put the same urban infrastructure to the test, from the power grid to the healthcare system.

The risk isn't just about feeling hot or cold. It's a public health problem that hits hardest for those who are already vulnerable: older adults, infants, people with chronic conditions, and anyone who works or sleeps outdoors. This guide follows the same structure we use for wildfires and earthquakes: before, during, and after.

Why Urban Risk Keeps Growing

• Heatwaves are getting longer, more frequent, and arriving earlier in the year.
• The urban heat island effect makes cities hold onto more heat than the surrounding countryside, especially overnight, when the body needs to cool down to rest.
• Power outages during peak demand, whether from air conditioning or heating, leave more people with no way to regulate the temperature at home right when they need it most.
• Many homes are poorly insulated against both extremes: a house that can't hold in heat during winter usually doesn't shield well against heat in summer either.

Before: What to Prepare Months in Advance

Prepare Your Home for Heat

• Install light-colored curtains or blinds that reflect sunlight on the most exposed windows.
• Air out the house at night and early morning, then close it up during the hottest hours.
• Check that your fan or air conditioning works before the season's first heatwave.

Prepare Your Home for Cold

• Seal doors and windows with weatherstripping to stop heat from leaking out.
• Service your heating system and chimney before the cold sets in.
• Insulate exposed pipes so they don't freeze or burst.

Build Your Emergency Kit

• Extra water and rehydration salts for heat; thermal blankets and layered warm clothing for cold.
• A thermometer to track the temperature inside your home.
• Flashlight, battery-powered radio, and a charged power bank.
• Regular medication and important documents in a waterproof folder.
• Enough food and water for your pets; they suffer from extreme temperatures too.

Track the Risk with Tools Already Available

• Follow official weather alerts by temperature level from your country's weather service.
• Turn on alerts in whatever weather app you already use for your area.
• Find out whether your city opens cooling centers or climate shelters in summer, or heated shelters in winter.

Identify Vulnerable People Near You

• Check in regularly on older neighbors or anyone living alone during a heatwave or cold snap.
• Keep contact details handy for family or neighbors who might need help regulating the temperature in their home.
• Know the location of the nearest health center.

During: How to Act When the Wave Hits

In Extreme Heat

• Drink water often, even if you don't feel thirsty. Cut back on alcohol and heavy caffeine.
• Avoid intense physical activity between midday and mid-afternoon, the hottest hours.
• Seek shade or air-conditioned spaces. Never leave people or pets inside a closed car.
• Wear light, loose, light-colored clothing, and cover your head if you go outside.
• Watch for signs of heatstroke: confusion, hot dry skin, a racing pulse. It's a medical emergency — get help right away.

In Extreme Cold

• Dress in layers and keep your hands, feet, and head dry; a lot of body heat is lost through the head.
• Don't run gas or charcoal heaters without proper ventilation. Carbon monoxide poisoning risk rises in winter.
• Let faucets drip slightly if temperatures drop sharply, to keep pipes from freezing.
• Watch for signs of hypothermia: uncontrollable shivering, confusion, slurred speech. It's a medical emergency — get help right away.

After: Once the Wave Passes

• Check the condition of your home: dampness, frozen or burst pipes, or damage from extended heating or air conditioning use.
• Reach out to the vulnerable people you identified earlier, especially if they were alone during the wave.
• Check on pets and plants after prolonged exposure.
• Store or repair the equipment you used (fans, heaters) for next time.

Preparedness Doesn't Depend on Having Signal

Weather alerts help, but what actually protects you is what you've already handled at home before the wave arrives: insulation, a kit, and a plan to check on the people who need it most. Get ready now, before the next temperature spike.

This guide covers heatwaves and cold waves only. If you want preparation for other scenarios (wildfires, earthquakes, power outages, cyberattacks), find more content on our site and download the complete citizen preparedness guide.