Temperatures exceeded 38 degrees Celsius in some parts of the city on Saturday, as Tropical Cyclone Dolphin brought a heatwave to Hong Kong. El Niño is a natural climate phenomenon whereby sea surface temperatures in the central and eastern equatorial Pacific become abnormally warm. A resident walks in a park when the city is struck by hot weather on May 23, 2025. Last month marked Hong Kong’s second-rainiest July on record, with a total of 20 amber rainstorm warnings and five red rainstorm warnings issued. The Intergovernmental Panel on Climate Change has warned that the intensity and frequency of heatwaves have continued to increase since the 1950s due to human-caused climate change.