Lightning Location Information

Number of lightning strokes detected over the Hong Kong territory in the past hour (7:00a.m. - 7:59a.m.):

Cloud-to-ground lightning: 0

Cloud-to-cloud lightning: 0

  Cloud-to-ground lightning count distribution over Hong Kong in the past hour

  Recent cloud-to-ground lightning count distribution over Hong Kong

  Number of lightning strokes detected over the Hong Kong territory today and for the past three days

  User Guide on "Lightning Alert Service" for managers of outdoor activity venues

  Video on how the Observatory detects lightning (in Chinese only)

  Maps of past lightning density in Hong Kong

Points to Note:

• The image shows cloud-to-ground or cloud-to-cloud lightning strokes as detected by the Lightning Location Network over the Pearl River Estuary in the past 30 minutes. The lightning records are updated at 5-minute intervals. Cloud-to-cloud lightning strokes are those detected strokes that did not reach the ground. As such, they might not affect people or facilities on the ground. However, it should be noted that they may sometimes precede cloud-to-ground strokes. The location as shown depicts roughly the starting point of the discharge from one cloud to the other.

• This page is best viewed with 1280 x 1024 resolution by Microsoft Internet Explorer 6.0, Netscape Communicator 7.0, Firefox 1.0, or above. If the above interactive map cannot be displayed properly, you can click here to view the latest lightning location picture immediately.

• The above map can be zoomed into street level so that the lightning symbol will be displayed over a street or a building. At this time, please bear in mind the uncertainty of lightning location and note that the actual location may be more than several hundred metres away from the displayed position. The lightning location network can detect lightning within a range of about 200 km from Hong Kong. Although the map can be scaled to show any part of the world, lightning location will only be displayed within the above-mentioned range.

• The network comprises six stations jointly established by the Hong Kong Observatory, the Guangdong Meteorological Bureau and the Macao Meteorological and Geophysical Bureau. The stations are located at Chung Hom Kok, Tsim Bei Tsui, Sha Tau Kok, Taipa in Macao, Sanshui and Huidong in Guangdong. (Click here to see the location of these stations)

• The accuracy in determining the location of cloud-to-ground lightning strokes is about 500 m within the network when all stations are operative. The lightning detection efficiency, i.e. the probability that a stroke with peak current greater than a certain level can be detected by the network, is estimated to be around 90 %. The location accuracy and detection efficiency will be reduced when the lightning stroke occurs outside of the network or when not all of the stations are operative. Since the lightning sensors are designed to detect mainly cloud-to-ground lightning, the efficiency of cloud-to-cloud lightning detection is not high and is estimated to range from 10% to 50%.

• There is no guarantee that all occurred lightning strokes can be detected and false detection of lightning strokes cannot be ruled out completely. As it takes time for communication and computation, there is normally a delay of a few minutes in the display of data. Other factors, including interruption to telecommunications services and power supply, can also affect the reliability and availability of the lightning information.

• By using the above map, you agree to be bound by Google's Terms of Use.

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