Paris was one of many European cities hit by a record-breaking heat wave at the end of June and early July 2025. NASA’s Ecosystem Spaceborne Thermal Radiometer Experiment on Space Station (ECOSTRESS) instrument recorded surface temperatures of 82 degrees Fahrenheit (23 degrees Celsius) at 6:57 a.m. local time on July 1. Extreme daytime air temperatures – of over 100 degrees F (38 degrees C) – prompted officials to close the summit of the Eiffel Tower on July 1 and 2.
In this visualization of ECOSTRESS data, dark red indicates higher temperatures while green and blue are cooler. The city is peppered with areas of several blocks where surface temperatures reached more than 80 F (27 C), including around the Eiffel Tower, before 7 a.m.
The ECOSTRESS instrument measures thermal infrared emissions from Earth’s surface. This enables researchers to monitor plant health, the progress of wildfires, land surface temperatures, and the burn risk to people from hot surfaces such as asphalt. Land surface temperatures are hotter than air temperatures during the day. Air temperatures, which are measured out of direct sunlight, are usually what meteorologists report in a weather forecast.
The instrument launched to the space station in 2018. Its primary mission is to identify plants’ thresholds for water use and water stress, giving insight into their ability to adapt to a warming climate. NASA’s Jet Propulsion Laboratory in Southern California built and manages the ECOSTRESS mission for the Earth Science Division in the Science Mission Directorate at NASA Headquarters in Washington. ECOSTRESS is an Earth Venture Instrument mission; the program is managed by NASA’s Earth System Science Pathfinder program at NASA’s Langley Research Center in Hampton, Virginia.
More information about ECOSTRESS is available here:
https://ecostress.jpl.nasa.gov/.