A thunderstorm under an active southwest monsoon brought 115.1 millimetres of rain in the early morning of July 16, breaking the 1992 record, the Hong Kong Observatory says.

Between 2am and 3am, the observatory recorded 115.1 millimetres of rainfall - the highest hourly rainfall since May 8, 1992 when 109.9 millimetres rain fell.

The observatory issued the black rainstorm warning signal at 2.50am. As the rain weakened, the black rainstorm signal was lowered at 5am and replaced by the amber rainstorm  signal at 5.45am. All rainstorm warnings were cancelled at 7.45am.

From midnight till 5am, more than 150 millimetres of rainfall were recorded on Hong Kong Island, Kowloon, Cheung Chau and Tseung Kwan O.

The observatory said strong winds with mean speeds exceeding 40 kilometres an hour are still expected from the southwest.

Those planning to participate in water sports activities and maritime operations should take care against strong winds and rough sea conditions.

The observatory believed the today's weather will remain overcast with heavy rain, squalls and thunderstorms and the southwest monsoon will continue to bring rainy weather to the territories in the next few days.

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