The Hong Kong Observatory warned on Friday that a storm in the area had intensified into a typhoon and was approaching the territory.
At 7 a.m. (2300 GMT), the typhoon, named Kai Tak, is estimated to be about 530 km (329 miles) from Hong Kong in the South China Sea and forecast to move slowly toward the southeastern coast of China.
The observatory said Friday would have sunny periods with isolated showers and thunderstorms in the evening, with maximum temperature reaching 31 degrees Celsius.
The weekend would be cloudy with showers, it said.