Hottest day of the year ushers in 9 days of rain, as Hong Kong logs over 6,000 instances of lightening on Friday

Hong Kong endured its hottest day of the year on Friday, June 5, 2026, as the Hong Kong Observatory (HKO) recorded a peak temperature of 34.6 degrees Celsius at its headquarters. The mercury climbed even higher in the northern parts of the territory, nearing 37 degrees Celsius.

Alongside the extreme heat, the city was also hit by significant lightning activity. The Observatory reported 1,263 instances of cloud-to-ground lightning and 4,859 cases of cloud-to-cloud lightning on Friday. Following this intense weather, the forecast predicts nine consecutive days of rain for the region.

The Observatory attributed the ongoing weather patterns to a broad trough of low pressure lingering over the coast of southern China and the northern South China Sea. An amber rainstorm warning was issued on Saturday morning due to violent gusts, raising concerns about potential flooding.

Friday also marked the hottest "Grain in Ear" solar term on record. This traditional period signifies the harvest of awny crops. In response to the escalating heatwaves, environmental NGO Friends of the Earth has urged the Hong Kong government to strengthen its climate adaptation policies and prioritize the climate crisis. The NGO highlighted the increasing intensity and frequency of heatwaves globally since the 1950s, largely due to human-caused climate change and the prevalence of greenhouse gases.

Research indicates that Hong Kong has already warmed by 1.7 degrees Celsius since the Industrial Revolution. Projections suggest that heat and humidity could reach lethal levels for extended periods by the end of the century, potentially making outdoor activities impossible in some areas. The Intergovernmental Panel on Climate Change has warned about the risks associated with these increasingly severe heatwaves.

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A broad trough of low pressure will linger over the vicinity of the coast of southern China to the northern part of the South China Sea during the weekend to midweek next week.