Dew Point, Heat Index & Wind Chill Calculator
Enter temperature, relative humidity, and wind speed to calculate dew point, heat index, and wind chill.
Last updated: September 5, 2026
Frequently asked questions
What is dew point?
The temperature air would need to cool to for it to become fully saturated with the moisture it already contains, causing condensation (dew). Higher dew points feel more humid and muggy regardless of the actual temperature reading.
What is heat index?
The "feels like" temperature when humidity is factored in with air temperature - high humidity reduces how effectively sweat evaporates to cool your body, making hot weather feel hotter than the thermometer alone suggests.
What is wind chill?
The "feels like" temperature when wind is factored in with cold air - wind strips away the thin layer of warmer air your body naturally holds near your skin, making cold weather feel colder than the thermometer alone suggests.
Why does the calculator sometimes show heat index or wind chill as N/A?
Both formulas are empirical regressions only validated within specific conditions - heat index needs warm, humid conditions (roughly 80°F+ with 40%+ humidity) and wind chill needs cold, breezy conditions (roughly 50°F or below with wind of at least 3 mph). Outside those ranges the formulas can produce misleading results, so they're hidden instead.
At what dew point does it start to feel muggy?
Most people start noticing humidity as uncomfortable around a 60-65°F dew point, with 70°F+ considered oppressive - below 55°F generally feels comfortable regardless of the air temperature.
Can heat index and wind chill both apply at the same time?
No - they're mutually exclusive by design, since heat index requires warm conditions (roughly 80°F+) and wind chill requires cold conditions (roughly 50°F or below). Outside either range, or in the gap between them, this calculator shows N/A for whichever doesn't apply.
Why does the calculator need wind speed for wind chill but not for heat index?
Wind chill's formula is specifically built around how moving air strips heat from exposed skin, so wind speed is a required input - heat index instead models how humidity impairs sweat evaporation, a process wind speed doesn't factor into in the standard NWS heat index formula this calculator uses.