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Heat index

Facts for Prelims (FFP)


Source: TH

 Context: Recently, Iran recorded a scorching heat index of 70 degrees Celsius (°C) in the coastal part of the country.

  • The heat index, also known as apparent temperature, is a crucial indicator that measures how the temperature feels to humans based on a combination of air temperature and relative humidity.
  • It provides a more accurate representation of how hot the weather actually feels compared to just the air temperature.


About Heat Index:

The heat index is calculated using a complex formula that considers factors such as air temperature, relative humidity, and dew point.  The dew point, the temperature at which air becomes saturated with moisture and forms dew, is a critical component in this calculation.

 Various countries have their own heat index measurement systems. For instance, Canada uses the Humidex, and the U.S. National Weather Service (NWS) has its own heat index chart.


Why measure the Heat Index?

  • The importance of measuring the heat index lies in its ability to assess the impact of heat on human health and well-being. High humidity during heatwaves can make the apparent temperature significantly higher than the actual air temperature, making it feel much hotter to people.
  • High heat index values can lead to heat stress, heat exhaustion, and even heatstroke, posing serious health risks. Monitoring the heat index is vital for public safety, especially during extreme heat events.
  • It helps authorities issue heat wave alerts, implement necessary precautions, and adapt to extreme heat conditions by adjusting work schedules and providing cooling solutions to protect public health and safety.