The official wind chill formula from the US National Weather Service and Environment Canada is only scientifically defined at 50°F (10°C) and below, with wind speeds above 3 mph (5 km/h). Plug in a mild spring day and a calculator that still spits out a "feels like" number is extrapolating a formula outside the range it was built for.
Wind chill formula, the official 2001 version
This calculator uses the joint NWS/Environment Canada formula, developed from clinical trials measuring actual heat loss from exposed skin — not the older, less accurate formula it replaced in 2001.
Feels like temperature calculator, with a validity check
Enter conditions outside the formula's valid range and this tool flags it explicitly, rather than silently displaying a number that doesn't mean anything scientifically.
Windchill chart, in °F/mph or °C/km/h
Switch units depending on what your local forecast uses — the underlying formula is unit-specific, so the calculator converts internally rather than approximating across unit systems.
