Up to six typhoons are expected to affect Hong Kong this year, which is less than normal, while annual rainfall will be near normal, Hong Kong Observatory Director Dr Lee Boon-ying said today.

He said the recent cold weather which affected parts of the mid-latitudes in the northern hemisphere was a part of normal short-term weather fluctuations.

The long-term global warming trend remains unchanged, he said, adding the mean temperature and the annual total rainfall show a rising trend.

"Between 1900 and 2000, the frequency of occurrence of heavy rain in Hong Kong has doubled," he said.

The Observatory launched a series of new online services today, such as radar images within 128km, digital weather forecast webpages and "My Observatory" � a location-specific weather service, providing weather data in finer detail.