Wind chill chart

A wind chill chart gives the wind chill temperature, the apparent temperature the body feels from the combined effect of air temperature and wind speed, read from a grid of temperature against wind speed. Moving air strips the thin warm layer at the skin and speeds heat loss, so a low temperature with a fresh wind chills exposed flesh far faster than the still-air value, with frostbite times falling steeply at the cold, windy corner. On a ship it sets clothing, exposure limits, and watch rotation for deck work in cold latitudes and polar waters. The Polar Code requires operators to account for low-temperature effects on personnel, and the chart is the planning tool for safe-working-time limits.