At 4 a.m. at the Hong Kong Observatory : Air temperature : 18 degrees Celsius Relative Humidity : 72 per cent The air temperatures at other places were: Hong Kong Observatory18 degrees ; King's Park17 degrees ; Wong Chuk Hang18 degrees ; Ta Kwu Ling15 degrees ; Lau Fau Shan16 degrees ; Tai Po16 degrees ; Sha Tin17 degrees ; Tuen Mun16 degrees ; Tseung Kwan O17 degrees ; Sai Kung17 degrees ; Cheung Chau17 degrees ; Chek Lap Kok17 degrees ; Tsing Yi17 degrees ; Shek Kong16 degrees ; Tsuen Wan Ho Koon15 degrees ; Tsuen Wan Shing Mun Valley16 degrees ; Hong Kong Park18 degrees ; Shau Kei Wan17 degrees ; Kowloon City17 degrees ; Happy Valley18 degrees ; Wong Tai Sin17 degrees ; Stanley18 degrees ; Kwun Tong16 degrees ; Sham Shui Po17 degrees ; Kai Tak Runway Park18 degrees ; Yuen Long Park16 degrees ; Tai Mei Tuk16 degrees . [air temperatures at other places]