Amid Record Heat Wave, Paris Authorities Use Drones to Identify Coolest Areas of the City

Most of the urban areas in Paris have a strict ban on drones, with zero exceptions allowed.

Until now.

During a recent heatwave, the French weather service—called Météo France—was given permission to use drones to help people find places where they could cool down.

The advantage of the drone is that it allows us to take a small sample of the air near the ground, in addition to various spaces above the ground. Then, we can scan these areas at several different points during the day.

– Cécile Demunck, Research Officer at the French National Meteorological Research Centre

The weather service is currently flying drones throughout the city, looking for areas where the heat is lowest. If you’re visiting the famous Paris, you might well see—or hear—a drone flying overhead during the day.

The fact that the weather service got permission to fly is actually pretty remarkable. Rules for drone operations in France are incredibly strict. In general, drones are prohibited from all urban areas in the country.

Here’s a screenshot of an interactive map that shows all the places where drones are banned throughout France:

How Drones Show Where It’s Coolest in Hot Cities

So how exactly are drones helping Parisians find out where it’s coolest?

First, the weather service flies through the city collecting heat data using drones equipped with thermal sensors.

After collecting the data it’s put into a digital map, which can be shared publicly so people have quick access to up-to-date information on where the heat is most and least intense throughout the city.

The focus of the map is on showing people where there are îlots de fraîcheur—cool spots.

These spots include indoors areas, like museums, churches, movie theaters, and other air conditioned public spaces, as well as public parks and shady outdoor spaces.

In addition to cool spots, the map shows the location of drinking fountains and brumisateurs, or cool water misters, where people can get water and cool down.

In the cool spots map, there are:

• 800 outdoor cool spots total
• 565 parks or green spaces (among these 800)
• 36 swimming areas
• 25 places with misters or water games
• 150 cool places that are open to the public, like churches and museums

All of this data is managed using Esri’s ArcGIS. View the map here.

One thing that stands out in the map is that unpaved areas are inherently cooler than areas that are paved. These areas stay cooler throughout the day, and they cool off faster at night.

In addition to identifying existing cool areas, local government has committed to creating 29 new “oasis courtyards” that will have greater vegetation, providing a refuge from the heat and helping cool the city as a whole.

Paris May Be the First, But It Won’t Be the Last

Like most big cities, Paris is much hotter than surrounding areas. This phenomenon is called the “urban heat island” effect.

Image source

According to the EPA, “‘Urban heat islands’ occur when cities replace natural land cover with dense concentrations of pavement, buildings, and other surfaces that absorb and retain heat. This effect increases energy costs (e.g., for air conditioning), air pollution levels, and heat-related illness and mortality.”

Put simply, when there’s a heat wave, cities aren’t just hot—they’re much, much hotter than surrounding areas.

As heat waves become more common, cities throughout the world are acknowledging this reality.

In Phoenix—which just experienced a record 19 days in a row of 110 degree or higher temperatures—there has been an Office of Heat Response and Mitigation for the last two years, with the first Chief Heat Officer in the U.S. (but probably not the last).

According to Phoenix’s Chief Heat Officer, whose name is David Hondula, extreme heat is one of the top killers among weather phenomena in the U.S., and it should be treated with just as much caution and intentional city planning as weather events like hurricanes or tropical storms.

As heat continues to rise, Hondula’s perspective will most likely be adapted by other cities. And we’re likely to see more and more cities start using drones to identify cool areas where residents can escape the heat.