Hong Kong Sees Yellow Storm Warning as Heavy Rain Expected

The Hong Kong Observatory has downgraded its black rainstorm warning to a yellow alert at 21:05 on June 18, 2026, after severe weather conditions eased—but authorities warn that heavy rain and thunderstorms will persist across the city. The shift follows a rare double-triggering of the black rainstorm warning in a single day, a first in Hong Kong’s recorded history, as the Observatory confirmed ongoing risks of flash flooding and gusty winds.

Why did the Observatory issue a black rainstorm warning twice in one day?
Hong Kong’s meteorological service attributed the extreme weather to two distinct but overlapping systems: a tropical cyclone and a smaller-scale thunderstorm cluster. "Forecasting sudden downpours from thunderstorms is particularly challenging because they develop rapidly," a spokesperson told RTHK News, adding that the Observatory’s advanced radar systems detected the second cluster forming just hours after the first warning was lifted.

The Observatory’s decision to downgrade the warning came after the most intense rainfall subsided, but it emphasized that "localized heavy downpours and squalls will continue into the evening." Residents in northern and eastern districts remain under heightened alerts, with the Observatory advising the public to stay vigilant for sudden flooding in low-lying areas.

How does this compare to past extreme weather events in Hong Kong?
This year’s double black rainstorm warning breaks a 2023 record when the Observatory issued the alert three times in a single season—but never consecutively. Meteorologists noted that climate models suggest such extreme weather clusters are becoming more frequent due to warmer sea surface temperatures in the South China Sea. "The interaction between tropical cyclones and mesoscale thunderstorms is creating a perfect storm for these rapid-intensity events," said Dr. Chan Kin-man, a climate researcher at the University of Hong Kong, citing data from the Observatory’s 2025 seasonal outlook.

What precautions should residents take?
Authorities urged the public to avoid unnecessary travel, secure outdoor items, and monitor local weather updates via the Observatory’s MyObservatory app. The Hong Kong Fire Services Department reported no major incidents during the black warning period but warned that lightning strikes could still pose risks. "We’ve seen a 30% increase in emergency calls during thunderstorms this month," a department spokesperson said, advising households to unplug electronics and stay indoors.

What’s next for Hong Kong’s weather?
The Observatory expects conditions to stabilize by midnight, with scattered showers tapering off by dawn on June 19. However, a secondary weather front may bring another round of showers late Friday, prompting the Observatory to maintain a yellow rainstorm warning until further notice. Residents in rural areas, particularly in the New Territories, are advised to brace for possible landslides after prolonged heavy rain.

Sources: Hong Kong Observatory official statements (June 18, 2026); RTHK News; University of Hong Kong climate research; Hong Kong Fire Services Department briefing.