Lyon faces intense tropical nights due to high humidity

Residents of Lyon, France, experienced an exceptionally difficult tropical night between August 19 and 20, 2026. Temperatures remained between 23°C and 25°C, but high humidity levels of 80% to 90% caused heat index values to reach between 32°C and 34°C.

Meteorologists from Lyon Météo attributed the suffocating conditions to Mediterranean winds and cloud cover that prevented nighttime cooling. This event marks the 30th tropical night—defined as a night where temperatures stay at or above 20°C—recorded in Lyon since June 1, 2026.

Local residents reported significant discomfort and difficulty sleeping due to the heavy, humid air. A slight reprieve is expected as minimum temperatures are forecasted to drop below 20°C across much of the Rhône department in the coming days.