The cold weather might be putting you off going out, let along going for a dip. But Hong Kong's unusually chilly waters didn't put off one unusual group of visitors.
A pod of about 100 false killer whales has been in local waters over the past two days, in what is thought to be the first mass sighting of the marine mammal in Hong Kong.
The animals were first spotted and videoed by crane operators at the Kwai Tsing container terminal as they made their way through Rambler Channel at about 3pm on Thursday.
At about 5.30pm, they were spotted by dolphin researchers heading from Ma Wan and the Brothers islands, north of Lantau. They were seen chasing fish, leaping out of the water and swimming next to ships.
They are believed to have left Hong Kong waters yesterday, according to the Hong Kong Dolphin Conservation Society, which tracked the animals and released two pictures of them.
The creatures are widely found in tropical and temperate waters, but rarely seen in Hong Kong, especially in groups.
In 2002, an attempt to rescue a false killer whale found stranded at Tai Long Sai Wan failed. False killer whales were found dead in 1983 at Tai Lam Chung, near Tuen Mun; in 2000 at Lantau; and at Sai Kung in 2005.
While they are known as false killer whales, the creatures, a member of the dolphin family, bear little resemblance to the orca except in the shape of their head and teeth. A mature false killer whale can be up to six metres long. Pods usually have between 30 and 50 members.
Dr Samuel Hung Ka-yiu, chairman of the society, said researchers found the sight of the pod deeply impressive. "If you looked around, they were everywhere. It was spectacular view."
Hung said it was not possible to speculate why the false killer whales were in Hong Kong or whether it could be down to this week's cold snap.
"I can't really think why [they were here]. But the group looked healthy and relaxed as they chased fish. They definitely did not get lost and they weren't in a distressed state," he said.
While visits by whales and dolphins - apart from local populations - are rare, a few unexpected visitors have turned up. A humpback whale was spotted in Victoria Harbour in 2009, while there was a suspected whale sighting off Pok Fu Lam in 2011.
The visits have been hailed a positive side-effect of work to clean up local waters.