Heat Stress Index
About Heat Stress
What this tool does
Weather and environment tools convert wind speeds between units (km/h, mph, knots, m/s), calculate humidity ratios, interpret UV index values, assess air quality, estimate cloud base altitude, and compute heat index and wind chill.
Why use this tool
Outdoor activities, aviation, and construction all depend on weather data interpretation. Knowing the actual heat index during a heatwave, or whether UV exposure warrants sunscreen, helps you make safer decisions.
How it works
Heat index and wind chill use NOAA regression equations. UV index maps solar irradiance to a 1-11+ scale. Cloud base is estimated from the temperature-dewpoint spread. Humidity calculations use the Magnus formula for saturation vapor pressure.
Pro tip
Wind chill only applies below 50 degrees F (10 degrees C) and at wind speeds above 3 mph. In calm conditions, the air temperature is the temperature you feel.
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