64 km image updates once every 6 minutes; 128 km and 256 km images update once every 12 minutes.
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 Rainfall distribution in the past hour.
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.