Wind Chill Calculator

How to use the wind chill calculator

1. Enter the air temperature in °C (the formula applies at 10 °C and below).
2. Enter the wind speed in km/h. No anemometer? 10 km/h moves leaves, 20 km/h small branches, 40 km/h makes large branches sway, 60 km/h makes walking hard.
3. Tick clothing is wet if you are soaked – you will get an extra warning.

How it is calculated

The calculator uses the North American wind chill index introduced by the US National Weather Service and Environment Canada in 2001: WC = 13.12 + 0.6215·T − 11.37·V^0.16 + 0.3965·T·V^0.16, with T in °C and V in km/h measured at 10 m height. It is valid for temperatures of 10 °C or below and wind of at least 4.8 km/h; outside that range the air temperature is shown.

The frostbite risk follows the feels-like value: above −10 °C low, down to −28 °C moderate (hypothermia with long exposure), from −28 °C exposed skin can freeze in 10–30 minutes, from −40 °C in 5–10 minutes and below −48 °C in under 5 minutes.

Staying safe in the cold

• A windproof shell adds more warmth in wind than another fleece. Cover face, ears and hands.
• Check each other’s faces for white, waxy patches – an early sign of frostbite.
• Wet clothing loses most of its insulation: change into dry layers or get to a fire at once.
• Wind chill affects people and animals, not objects: water still freezes only below 0 °C.
• The index is an estimate for dry, shaded skin – sun lowers the effect, wet skin and exhaustion raise it.