The HK Observatory dropped the cold weather warning at midday, after it had been issued for a record 204.75 hours. The warning was first issued at 11.15pm on January 18.

Scientific Officer Lee Kwok-lun said the observatory considers three factors in issuing the warning - temperature, humidity and wind speed.

He said although 12 degrees Celsius is an important reference point, it does not necessarily mean that when the temperature falls to 12 degrees a cold weather warning will be issued automatically.

Humidity and wind speeds at the time will also be taken into account in making a final decision.

The warning system was established in December 1999.