Feels like temperature calculator
A feels like temperature calculator shows how the weather registers on the body, which is not the number on a thermometer. Enter air temperature, humidity and wind in km/h: it picks the heat index or the wind chill, and if neither applies, it leaves the air temperature as it is.
Feels like
-12 °C
Wind chill (NWS)
Feels like temperature meaning: which index applies and when
The calculator follows three rules. At 27 °C and above it computes the heat index, which needs temperature and humidity. In cold weather with wind it computes the wind chill, which needs temperature and wind speed. In every other case the feels like temperature equals the air temperature, and the calculator says so.
Both indices describe how the weather feels to the body. They do not change the air temperature, and a thermometer outside would read the same.
Heat index: temperature and humidity
The heat index uses the algorithm of the US National Weather Service (NWS, NOAA): the Rothfusz regression with adjustments (algorithm description). It takes temperature and humidity and applies at 80 °F (about 27 °C) and above. Below that, the calculator does not use it.
For fatigue in heat and high humidity, see Heat, humidity, and fatigue: how weather drains your energy.
Wind chill and where it is not defined
Wind chill uses the NWS formula from 2001 (chart and description). It is defined only at temperatures of 50 °F (10 °C) or lower and wind above 3 mph, about 4.8 km/h. With lighter wind or warmer weather the index does not exist, and the calculator does not show it.
If temperature and wind are outside the range of both indices, you will see a message that there is no adjustment. In that case the feels like temperature is the air temperature.
This is an informational tool. It gives no medical advice and does not assess how you feel. For acute or unusual pain, see a doctor.