Temperature plunged below the freezing point in some parts of New Territories this morning, with farmers reporting large scale damages to their crops. The mercury in Ta Kwu Ling touched 0.9 degrees – the lowest in 33 years since its record began. The observatory pointed to a phenomenon called “radiative cooling” for the plunge, while predicting temperatures to get warmer in the next few days before a reverse at the beginning of next week. Radiation cooling is a maximum cooling of the ground which occurs under clear skies, light winds and dry conditions. In winter, a large temperature difference sometimes exists between the urban area and the New Territories.