The use of backscattered power of a LIDAR at the Hong Kong International Airport (HKIA) to generate visibility map was studied in Chan (2003) based on an empirical relationship between the extinction coefficient at the LIDAR's wavelength (about 2 microns) and that for the visible range in hazy weather. This paper discusses the development of a new algorithm that combines the LIDAR's backscattered power and measurements from visibility sensors (forward scatterers) to generate visibility map in different weather situations, without the use of empirical relationship for specific weather type. The performance of the algorithm in different low-visibility weather conditions, such as haze, fog/mist and rain, will be presented. The visibility map is found to depict many salient features of low-visibility events, such as the arrival and clearance of haze and fog. Its potential application in real-time visibility monitoring at an airport will be discussed.