All classes in morning and whole-day schools in Hong Kong were suspended on Monday after the red rainstorm warning signal was raised as heavy rainfall pounded the city.

The Education Bureau made the announcement at 5:30 am after the red rainstorm warning, which means heavy rain exceeding 50 millimeters in an hour had fallen or was expected to fall, had been in effect for over four hours.

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"As the red tainstorm warning signal is now in force, classes of all AM schools and whole-day schools are suspended today," the bureau said.

More than 60 millimeters of rainfall was recorded over many places in the territory, according to the Hong Kong Observatory.

Rainfall even exceeded 100 millimeters over the Islands District and Tuen Mun, it added.

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The observatory eventually lowered the rainstorm warning to amber at 6:05 am before canceling it about an hour later.

Thunderstorm warning

A thunderstorm warning issued at 12:25 pm on Sunday remained in force after it was extended until 2:00 pm Monday. The HKO said isolated squally thunderstorms were expected to occur over Hong Kong.

The observatory added that the Strong Monsoon Signal was also in force as strong winds with mean speed exceeding 40 kilometers an hour were expected from the southeast.