The Wind Chill Index is a measure that describes how cold it feels outside when the wind is factored in with the actual air temperature. It helps people understand the potential for frostbite and hypothermia by indicating the combined effect of wind and temperature on exposed skin. When the wind blows, it removes the thin layer of warm air that surrounds our bodies, making us feel colder than the actual temperature. The Wind Chill Index is especially important for outdoor activities in winter, as it can guide individuals in dressing appropriately to stay safe in cold conditions.