Heat Stroke Risk Calculator
This tool estimates the risk of heat-related illness by calculating the Heat Index, which is how hot it really feels when relative humidity is combined with the air temperature.
Heat Index & Risk Levels (NWS):- 90-103°F (32-39°C): Extreme Caution. Heat cramps and heat exhaustion are possible.
- 103-124°F (39-51°C): Danger. Heat cramps and heat exhaustion are likely, and heat stroke is possible with prolonged activity.
- 125°F+ (52°C+): Extreme Danger. Heat stroke is highly likely.
This calculator uses the U.S. National Weather Service's multiple regression equation to determine the Heat Index (HI). The formula is expressed as follows:
$$ HI = c_1 + c_2T + c_3R + c_4TR + c_5T^2 + c_6R^2 + c_7T^2R + c_8TR^2 + c_9T^2R^2 $$
Where:
T = Ambient air temperature in degrees Fahrenheit (°F)
R = Relative humidity in percent (%)
The coefficients ($c_1$ through $c_9$) are constants derived from the model. This formula is precise for T ≥ 80°F and R ≥ 40%.
- National Weather Service (NWS). Heat Index Information. Learn More.
- Centers for Disease Control and Prevention (CDC). Extreme Heat. Learn More.
This calculator is for informational purposes only and is not a substitute for professional medical advice or personal judgment. Individual risk can vary based on health, age, hydration, and other factors. If you suspect someone has a heat-related illness, seek emergency medical help immediately.
Estimate heat illness risk based on temperature, humidity, and activity.