"Historical Purple Rainfall Event in CDMX": Segiagua - Depiction of the Aug. 10 Rainfall Scene in the city
Historic Rain Event in Mexico City: The 'Purple Stain' of August 10, 2025
On August 10, 2025, Mexico City experienced one of its most significant rain events in recent history. The rainfall, described as "extraordinary in its volume and intensity," was more than half the usual monthly August rainfall, totalling 84 mm, causing widespread flooding and major disruptions.
The meteorological representation of this event was a large purple stain on the isohyets map. This purple stain signified areas with extremely heavy rainfall, triggering a "Plan Tlaloque purple alert" by city emergency services. The purple color on isohyets maps symbolizes the highest precipitation intensity zones.
José Mario Esparza, Secretary of Integrated Water Management (Segiagua), detailed that the rain on the past Sunday generated this "purple stain" on the map of isohyets. The purple stain was most visible in the center of the city, where the purple alert, the maximum for rainfall, was activated.
The rainfall on August 10 broke several records. It was the highest rainfall recorded in a single day in the city's history, surpassing the previous record of 67 mm set in 1952. Approximately 50 millimeters of the rain on August 10 fell in just 20 minutes, making it an extremely localized and intense storm.
The impacts of the rain were mainly in the center and north-central part of the capital. The city's historic center (Zócalo) was flooded, overwhelming drainage, and causing major airport operational halts. The rain affected tens of thousands of travelers.
Despite the challenges, the Metro operated normally after the rains, but Metrobus reduced routes due to flooding. This event highlighted vulnerabilities in urban infrastructure to such extreme localized storms and the critical role of emergency protocols during extraordinary rainfall.
The 'purple stain' on the map thus symbolizes the historic intensity and spatial concentration of rainfall on that day, marking August 10, 2025, as a significant date in Mexico City's recent meteorological and urban flood management history.
[1] News article 1 [2] News article 2 [3] News article 3
- Weather forecasting models in the days leading up to August 10, 2025, had predicted the likelihood of an extraordinary rain event in Mexico City, but the actual rainfall exceeded expectations.
- In the aftermath of the August 10 rain event, there has been a call for improved weather-forecasting accuracy and urban infrastructure resilience against such extreme weather conditions.
