Temperatures in Hong Kong could plunge to as low as 10 degrees Celsius (50 Fahrenheit) this week, with a cold front expected to sweep across the coast of Guangdong province from Tuesday night.

According to the latest nine-day forecast by the Hong Kong Observatory, the relatively warm weather so far – up to 28 degrees Celsius – would remain until Tuesday, with the mercury dropping significantly from Wednesday to as low as 15 degrees.

It will dip further – ranging between 13 and 17 degrees – in the latter part of the week under the influence of an intense northeast monsoon.

Temperatures​​ could go as low as 10 degrees at Ta Kwu Ling, and 12 degrees at Sheung Shui, Tin Shui Wai and Tai Po on Friday, before sunny intervals return over the next weekend, according to the forecast.

The Observatory attributed the temperature drop to a cold front, which is expected to move across the coast of Guangdong between Tuesday night and Wednesday morning.

“Winds will strengthen from the north and the weather will become cool appreciably over the region on Wednesday,” it said.

Lo Ka-wai, a scientific officer at the Observatory, said it was common the chilly weather would ease before the next cold front arrived in winter.

“When a cold front or monsoon arrives, the temperature will drop. As its impact eases, the temperature will climb up slightly until the next monsoon arrives,” Lo said.

The Observatory also predicted the temperatures between November and January would be normal or above normal due to the influence of global warming and the effects of the city’s urbanisation on weather, as part of a long-term rising trend.

The switch to cooler weather is a welcome change from the intense heat of the summer, with July becoming the hottest month since records began in 1884.

Another record was broken on September 13 when the Observatory reported temperatures of 35.9 degrees, making it the warmest day documented for the month.

The Observatory said there were only two cold days – with daily minimum temperatures of 12 degrees or below – last December, down from three during the same month in 2020. No cold day was recorded in December 2019.