Choose a season
Each season uses a different formula
Summer feels-like temperature depends on air temperature and humidity — high humidity slows sweat evaporation, making it feel hotter. Winter feels-like temperature depends on air temperature and wind speed — wind strips heat from skin faster. That is why this calculator asks you to pick a season first.
The formulas used
Summer uses the wet-bulb-based formula that national weather services (including Korea’s KMA since June 2022) apply, and winter uses the wind chill formula shared by the US National Weather Service, Environment Canada, and KMA. Wet-bulb temperature is not measured directly — it is approximated from air temperature and relative humidity using the Stull (2011) approximation.
Weak wind leaves winter feels-like temperature unchanged
Below 4.8 km/h, wind has a negligible cooling effect, so the feels-like temperature is set equal to the actual air temperature.
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Frequently asked questions
QWhy are summer and winter calculated differently?
Summer feels-like temperature is set by how much humidity slows sweat evaporation, while winter feels-like temperature is set by how fast wind strips heat from skin. They are different physical effects, so they use different formulas.
QWhy isn’t wet-bulb temperature entered directly?
It is normally measured with a wet-bulb thermometer, which is hard to do at home, so this calculator approximates it from air temperature and relative humidity using the Stull (2011) formula.
QWhat happens in winter when there is almost no wind?
Below 4.8 km/h, wind’s cooling effect is considered negligible, so the feels-like temperature is calculated as equal to the actual air temperature.