📘 Heat Index Formula (Celsius)
The Heat Index (HI) tells you how hot it feels when humidity is factored with air temperature.
📐 Main Formula (Using Temperature in °C and RH):
HI = -8.784695 + 1.61139411×T + 2.338549×RH
- 0.14611605×T×RH - 0.012308094×T²
- 0.016424828×RH² + 0.002211732×T²×RH
+ 0.00072546×T×RH² - 0.000003582×T²×RH²
📐 If Dew Point is Used:
Convert Dew Point (D) to Relative Humidity (RH):
RH = 100 × (exp((17.625 × D)/(243.04 + D)) / exp((17.625 × T)/(243.04 + T)))
🔍 Example:
Air Temperature = 32°C, RH = 70% → Heat Index ≈ 41°C