Explained | What is a heat index and why is it important to measure?

Source: The post is based on the article “Explained | What is a heat index and why is it important to measure?” published in The Hindu on 8th September 2023

What is the News?

Recently, Iran recorded a scorching heat index of 70 degrees Celsius (°C) in the coastal part of the country, a metric at which survival of life is difficult.

What is the heat index?

Heat index, also known as apparent temperature, is a measure of how the temperature feels to humans. 

Relative humidity is an important factor that determines heat index along with air temperature.

How is the Heat Index calculated?

The calculation of the heat index involves a complex formula developed by Dr. Robert Steadman in 1979.Dr. Steadman’s formula considers a typical adult human of certain height and weight and incorporates the dew point.Dew Point is the temperature at which air cannot hold any more water vapour, and droplets of water begin to form.In his calculations, Dr. Steadman used 14 °C as the dew point in his calculations.

Some countries, like Canada, have their own indices to measure the heat index.

In 2024, India is scheduled to launch its own heat index to quantify the impact of heat on its population and generate impact-based heatwave alerts for specific locations.

Why is it important to measure the Heat Index?

Impact on Health: High humidity combined with high temperatures can lead to heat stress and heat-related illnesses.It’s crucial to know when conditions are ripe for these health risks so that people can take precautions.

Safety: Heat index values help determine the level of caution needed during hot weather. It provides guidance on when it’s safe to engage in physical activity outdoors and when it’s potentially dangerous, preventing heat-related illnesses and even fatalities.

Climate Change: As temperatures rise due to climate change, we can expect more extreme heat conditions.Monitoring the heat index allows us to prepare, adapt, and implement strategies like early warnings, adjusted work schedules, and sustainable cooling solutions to cope with these extremes.