Check cold weather safety limits.
Cold injury risk tracks wind chill rather than air temperature, because wind strips the insulating boundary layer from skin. The standard wind chill equation applies above about 5 km/h, and damp clothing is treated as a further three degrees because wet insulation conducts heat many times faster than dry. Frostbite time thresholds follow the published exposure bands, and covering skin extends them substantially.
Wind chill and exposure limit
Wind chill (C) = 13.12 + 0.6215 T - 11.37 V^0.16 + 0.3965 T x V^0.16, minus 3 C if clothing is wet; frostbite time from standard wind chill bands
Cold injury risk varies with age, circulation, medication, alcohol, fatigue and individual susceptibility. These figures are general guidance only — follow official cold weather warnings and seek medical help for suspected frostbite or hypothermia.
Exposed skin can freeze in about 30 minutes near -28 C wind chill, in around 10 minutes near -40 C, and in under 5 minutes below about -48 C.
Water conducts heat roughly 25 times better than still air. Wet insulation loses most of its value, which is why staying dry matters more than adding layers.
No — it only describes heat loss from warm skin. Water pipes and cars freeze according to air temperature, not wind chill.