Heat Index Calculator (Apparent Temperature & Humidity)
Environmental health and meteorology tool. Evaluates body difficulty in dissipating heat through sweat evaporation in high humidity.
Input Parameters
Instant Calculation Result
Adjust values on the left to calculate live results.
In-Depth Guide & Mathematical Methodology
☀️ NWS Heat Index Hazard Categories
80°F - 90°F: Caution (fatigue possible with prolonged exposure).
90°F - 103°F: Extreme Caution (sunstroke, heat cramps, and heat exhaustion possible).
103°F - 124°F: Danger (heat exhaustion likely, heatstroke possible).
≥ 125°F: Extreme Danger (heatstroke highly likely).
Frequently Asked Questions (FAQ)
What is the Heat Index Calculator (Apparent Temperature & Humidity) and how does it work?
Environmental health and meteorology tool. Evaluates body difficulty in dissipating heat through sweat evaporation in high humidity.
How do I use this Heat Index Calculator (Apparent Temperature & Humidity)?
Enter Air Temperature in Fahrenheit (°F) or Celsius (°C, min 80°F / 27°C). Enter Relative Humidity (%) of ambient air. View Calculated Heat Index and thermal stress hazard category.
What mathematical formula is used in this calculation?
NWS Rothfusz Equation: HI = -42.379 + 2.049*T + 10.143*RH - 0.224*T*RH - 0.0068*T² - 0.054*RH² + ...
Is the Heat Index Calculator (Apparent Temperature & Humidity) on FindCalculator free to use?
Yes, all 330+ interactive tools on FindCalculator.online are 100% free, run directly in your browser without registration, and do not store your private calculation data.