Nashville issues 7th heat advisory this summer

Heat is the leading cause of weather-related deaths in the U.S. and globally. Heat can strain organs in bodies as people try to cool down, worsening conditions like heart disease, diabetes and asthma. 

Heat risk communication like heat advisories, however, varies across the country.

In Nashville, a forecasted daytime heat index of 105 degrees will trigger a heat advisory. The National Weather Service issued two heat advisories in the city for Tuesday and Wednesday, bringing the total number of heat advisories this summer to seven. 

This threshold for communication is not consistent. New England, for example, has a heat index threshold of 95 degrees, based on research by its public health agencies. Texas has seven different thresholds within its borders. Many NWS offices will also issue heat advisories when temperatures do not dip below 75 degrees at night. 

And not everyone listens to these advisories. Risk perceptions can vary between neighborhoods in cities and among social groups, according to research by the Yale Program on Climate Change Communication. People over the age of 65 and white men are less likely to perceive heat risks than other populations. 

More: With fewer trees and more concrete, Nashville is heating up. What’s the plan?

The number of people exposed to extreme heat is growing exponentially across the globe due to climate change. Heat-related mortality for people over age 65 increased by approximately 85% between 2000–2004 and 2017–2021, according to the World Health Organization. 

Last year was the hottest year on record for Earth and Nashville. 2023 was also the hottest year for the oceans. This global warming is primarily caused by the burning of fossil fuels, deforestation and agriculture. Nashville is also getting hotter as the city loses trees and adds concrete. 

More: Nashville is 53-56% forested. Here’s why it probably doesn’t seem that way.

Between May 2023 and May 2024, there were 76 extreme heatwaves across 90 countries. Climate change added an average of 26 extreme heat days, while some countries like Ecuador and El Savador had 170 and 148 excess heat days, respectively, according to an analysis by Climate Central, Red Cross Red Crescent Climate Centre and World Weather Attribution. 

In Nashville, through July 30, the city is now on track to have its third-hottest year on record, based on the average mean temperature. The city has also had its second-hottest average low temperature thus far, according to the Southeast Regional Climate Center.