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Friday, 10th December 2010

Weather on the move

The Observatory website has enjoyed increasing popularity, with the number of page visits increasing from a couple of millions in the mid-1990s to 1.6 billion in 2009. In the advent of smartphones and netbooks, the Observatory has developed products to ensure users get the latest weather information anywhere and at any time. These have already attracted a considerable number of members of the public. This blog introduces some of the products.

A smartphone allows the automatic determination of the user's location (a function that can be turned off to protect the user's privacy). The beauty of this is that weather information specific to the user's location can be 'pushed' to him/her. Of course, he/she has the option to select any location in Hong Kong other than their own.

Lightning alert service

The lightning alert service allows the user to access the latest distribution of lightning strikes detected in Hong Kong. The user can select up to 3 concentric alert circles (5 km, 15 km or 30 km) so that he/she will be alerted once lightning is detected within any of the circles. This enables a graded response by the user in accordance with the proximity of lightning. The feature proves to be very useful in planning outdoor activities such as hiking, barbecuing, partying and swimming. We know that swimming pool operators have used this service to great effect in their decision to close or re-open pools.

Figure 1     Location-specific lightning alert with up to 3 selectable circles
Figure 1      Location-specific lightning alert with up to 3 selectable circles


Named by H.G. Wai, our former Assistant Director, MyObservatory has gained instant popularity since its launch early this year. This service automatically seeks out information at the weather station closest to the phone user. Weather tends to vary somewhat across the territory of Hong Kong by virtue of the complex terrain and coastal settings here (for instance temperatures can vary by more than 10 degrees Celsius across Hong Kong in wintertime). For this reason, there are now over 30 weather stations here providing public with the latest temperature, humidity, sky photo, rainfall and wind information. MyObservatory automatically picks the appropriate weather station according to the user's location.

In response to public demand, MyObservatory was upgraded in mid-year to include more weather information such as 7-day forecast and weather radar pictures. It has stayed in the list of top free downloads for some time now. In fact, the visit figure has skyrocketed to 140 millions in just a few months. A similar function is also available on Android and PDA platforms.

Figure 2     MyObservatory on iPhoneFigure 3     MyObservatory on Android


Twitter as a social networking service offers a great way for weather warning and information dissemination. The Observatory's experimental Twitter service was launched in September. The latest weather warnings (including tropical cyclone, rainstorm, thunderstorm, and hot/cold weather warnings), in the form of 'tweets', are now released on the Observatory Twitter profile "ObservatoryHK" and distributed to 'followers', i.e. users subscribing to Observatory tweets. Other information is also disseminated, e.g. new products and latest news from the Observatory, and release of the Director's blog . The number of followers has grown from a modest few hundreds in the beginning to thousands in the space of a few months.

Figure 4     Twitter as a means to disseminate weather warnings
Figure 4      Twitter as a means to disseminate weather warnings

Weather knows no boundaries

The Observatory has launched in August an experimental webpage displaying in real time weather warnings issued by Guangdong, Macao and Hong Kong. In this PRD (Pearl River Delta) service, the latest weather warnings from all these weather services are integrated onto a single page for easy access by people. It would not have been possible without the co-operation of our Guangdong, Shenzhen and Macao counterparts. Commuters and school children having to cross the borders each day will find it a very handy service on their phones.

Figure 5     PRD weather warnings at your fingertips
Figure 5      PRD weather warnings at your fingertips

If you have other ideas, let us know.

B.Y. Lee

Links to the above products:

Lightning Alert Services:

MyObservatory (iPhone version):

MyObservatory (PDA version):


Greater Pearl River Delta Weather Warning Webpage (Beta Version):

Last revision date: <17 Jan 2013>