It’s predicting that between five and eight typhoons will come within 500 kilometres of the city, slightly higher than the usual four to seven tropical cyclones.
Director Cheng Cho-ming said 2020 was Hong Kong’s second warmest year on record, with an average mean temperature of 24.4 degrees.
It was the warmest summer on record, with mean temperatures reaching 29.6 degrees, and the year’s 50 Hot Nights (where the minimum temperature is 29 degrees or above) and 47 Very Hot Days (where temperatures hit 33 degrees) were also records.
Cheng said it is difficult to say if the city would break these records again in the coming year, but he described the faster rate of increase in average temperatures over the past three decades as “significant” and “worrying”.
He said climate change may also result to stronger typhoons.
“The effect of global warming, the mean temperature is in the rise. That means it can hold more water vapour. And that water vapour is energy for tropical cyclone to develop,” he explained.
“So the general trend is that, if this continues, there will be more energy for the tropical cyclone to develop. That means tropical cyclone can develop into a very intense one.”
He said it was difficult to say whether cyclones would definitely be stronger, or how close they would get to Hong Kong – but they would come earlier with higher temperatures detected over the Pacific Ocean.
Cheng also warned people to expect more “extreme weather”, with either no or very heavy rain this summer.
In response to the more unstable weather, the Observatory will launch a “Localised Heavy Rain Advisory” service in the second quarter of 2021, which will tell the public where to expect heavy rain in the next hour, as well as provide rainfall forecasts.