Visibility levels at the airport have been at near record lows as hazy weather marked the first month of the year. For January, visibility was below 8km for 449 hours, the second worst figures since the airport opened in 1997 and 237 hours more than the average. The worst month was January last year, when the Observatory recorded 484 hours of poor visibility at the airport. Observatory scientific officer Cheung Ping said the trapping of pollution particles, especially at Chap Lap Kok, caused the problem. 'There are always winds blowing from the sea to the area and its natural landscape means pollutants will often stay there, affecting visibility,' he said. The Observatory also reported that temperatures last month were warmer than usual. The mean temperature was 16.4 degrees Celsius, 0.6 degrees above normal. A bigger difference was seen from the mean daily minimum, which was 14.7 degrees, 1.1 degrees higher than normal. The mean daily maximum, however, was 0.2 degrees lower than normal at 18.4 degrees. The city recorded its lowest temperature of the month, 8 degrees, on January 7. At 16.3mm, the month's rainfall was 7.1mm less than normal. The mean relative humidity had been 79 per cent, 8 per cent higher than usual.