Wind Chill Calculator

What Is Wind Chill?

Wind chill is the perceived decrease in air temperature caused by wind. Moving air strips heat from exposed skin faster than still air at the same temperature. A temperature of -10 C (14 F) with 30 km/h wind produces a wind chill of -20 C (-4 F), meaning your skin loses heat at the same rate as it would in calm air at -20 C. Enter the air temperature and wind speed in the calculator above to find the wind chill factor, frostbite risk time, and safety recommendations for your conditions.

How Is Wind Chill Calculated?

The current wind chill formula used by the US and Canada (adopted in 2001) is: WC = 13.12 + 0.6215T - 11.37V^0.16 + 0.3965TV^0.16, where T is temperature in Celsius and V is wind speed in km/h at 10-meter height. The older formula (Siple-Passel, 1945) produced more extreme values that overstated the danger. The current formula was developed from clinical trials where volunteers' skin temperatures were measured in a refrigerated wind tunnel, producing results that match actual human thermal experience more accurately than the purely theoretical older model.

Wind Chill Danger Levels

0 to -9 C (32 to 15 F): Slight risk for prolonged exposure. Dress in layers. -10 to -27 C (14 to -17 F): Risk of frostbite on exposed skin within 30 minutes. Cover extremities. -28 to -39 C (-18 to -38 F): Frostbite possible within 10-30 minutes. Limit outdoor time. -40 to -47 C (-40 to -53 F): Frostbite within 5-10 minutes. Dangerous conditions. Below -48 C (below -54 F): Frostbite within minutes. Exposed skin freezes rapidly. Life-threatening conditions. Environment Canada issues wind chill warnings at -35 to -40 C depending on the region.

How Does Wind Make Cold More Dangerous?

Your body maintains a thin layer of warm air next to the skin called the boundary layer. Wind strips this insulating layer away, forcing your body to continuously reheat the air next to the skin. Faster wind removes heat faster, creating a greater wind chill effect. At -15 C in calm air, your boundary layer provides moderate insulation. At -15 C with 40 km/h wind, that layer is constantly torn away, and your skin temperature drops rapidly toward the actual air temperature. However, wind chill only affects living tissue and objects that generate heat. An inanimate object like a car engine cannot cool below the actual air temperature regardless of wind speed.

Frostbite and Hypothermia Prevention

Frostbite occurs when skin tissue freezes, typically starting at extremities: fingers, toes, nose, ears, and cheeks. Symptoms progress from numbness and white pale skin (frostnip, reversible) to hard waxy skin with blisters (superficial frostbite) to deep tissue damage affecting muscles and bone (deep frostbite, potentially requiring amputation). Prevention: wear insulated windproof layers covering all skin. Mittens retain heat better than gloves. A balaclava protects the face. Stay dry because wet clothing loses insulation dramatically. Hypothermia occurs when core body temperature drops below 35 C (95 F), causing shivering, confusion, loss of coordination, and eventually cardiac arrest.

Wind Chill for Outdoor Activities

Runners and cyclists face amplified wind chill because their movement creates additional effective wind speed. Running at 15 km/h into a 20 km/h headwind experiences 35 km/h effective wind speed on exposed skin. Skiing at 50 km/h in -10 C creates extreme wind chill on any exposed facial skin. Winter hikers should plan for conditions at the summit where winds are typically 2-3 times stronger than at the trailhead. Ice fishers sitting on frozen lakes face sustained wind exposure without natural windbreaks. For all winter activities, check the wind chill before heading out and carry emergency shelter and extra insulation in case conditions deteriorate unexpectedly.

Wind Chill Around the World

The most extreme wind chills on Earth occur in Antarctica, where temperatures below -60 C combined with sustained winds create wind chills below -90 C. In populated areas, northern Canada, Siberia, and Scandinavia regularly experience wind chills below -40 C. The coldest wind chill recorded at an inhabited location is approximately -78 C in Yakutsk, Russia. In the contiguous US, the northern plains (Minnesota, North Dakota, Montana) see the most extreme wind chills, occasionally dropping below -50 C during Arctic outbreaks. These conditions close schools, halt outdoor work, and can make exposed skin freeze in under two minutes.

Frequently asked questions