Enter the current temperature and relative humidity into the calculator to determine the heat index.

Heat Index Formula

The following formula is used to calculate a heat index.

HI = .5 * [ T + 61.0 + [(T-68)*.12] + (RH*.094)]

Temperature (F) measures the average kinetic energy of the particles in a substance on the Fahrenheit scale.

Relative humidity refers to the amount of moisture in the air compared to the maximum amount it can hold at a given temperature, expressed as a percentage.

Heat Index Definition

Heat Index is a measure that combines air temperature and relative humidity to determine how hot it feels to the human body. It is important because it helps us understand the potential risk of heat-related illnesses such as heat stroke and heat exhaustion.

By considering both temperature and humidity, the Heat Index provides a more accurate representation of the actual discomfort caused by heat.

This information is crucial for individuals who work or engage in outdoor activities, as it helps them take appropriate precautions to prevent heat-related health problems.


Heat Index Example

How to calculate heat index?

  1. First, determine the relative humidity.

    Using the calculator linked above, determine the relative humidity.

  2. Next, determine the current temperature.

    Measure the temperature using an accurate thermometer.

  3. Finally, calculate the heat index.

    Using the HI formula, determine the heat index using the information from steps 1 and 2.

FAQ

What is a heat index?

A heat index is the temperature that it “feels” like when taking into account relative humidity. Since human bodies use perspiration to cool off, the higher the humidity the hotter it feels like since that makes it harder to cool off.



heat index calculator
heat index formula