Among weather-related hazards, which type is responsible for the greatest number of annual human deaths?

• A. Extreme heat
• B. Wildfire
• C. Extreme cold
• D. Flooding

Answer: (A)

Extreme heat causes the most deaths each year because heat exposure can affect large populations over multiple days, leading to heat-related illnesses such as heat stroke, dehydration, and cardiovascular or respiratory complications. Vulnerable groups—older adults, people with chronic conditions, outdoor workers, and those without access to air conditioning—are at particularly high risk, and urban heat islands can intensify exposure. Heat waves also stress infrastructure, like power and cooling systems, which can worsen outcomes when cooling isn't available. By spreading across many regions and lasting longer than a single event, extreme heat accumulates a higher mortality burden annually than floods, extreme cold, or wildfires, making it the leading weather-related cause of death.