The image shows the rainfall rate at a height of 3 km above mean sea level, as observed by Hong Kong Observatory's weather radar. HKT means Hong Kong Time. The colour scale on the right indicates the magnitude of the rainfall rate.
Weather radar detects rain in the atmosphere by measuring the intensity of signals reflected from raindrops. This signal intensity depends on a number of factors. Generally speaking, the larger the raindrops are and the more their amount is, the stronger is the reflected signal.
For the latest rainfall recorded in various regions of Hong Kong, please click here.
An empirical formula is used to convert the signal intensity into rainfall rate. Thus, the rainfall rate presented here is only an estimate. Furthermore, the rainfall rate refers to the 3-km level, so that the rainfall reaching ground could be very different. For surface rainfall distribution over Hong Kong, please visit http://www.weather.gov.hk/wxinfo/rainfall/isohyete.shtml.
Weather radar may occasionally pick up reflected signals from sources other than rain, such as reflections from clouds, trees, buildings, birds, hills, sea waves and even distant land mass. Please exercise care when viewing the image, as these signals may occasionally show up on the radar image.
The time of the radar image represents the time when the radar completes its scans. Usually, it will take about half an hour to generate the radar image and upload it to the website.
* The icon / link above contains radar imagery overlaid with geographical information (Note: require geo-browser software supporting KML data format. Please click here for "Method to Use").