A five-year-old girl has died in a lake in Victoria's north, bringing the total number of water-related deaths across the state to four in three days.
Emergency services responded to reports of a missing child at Lake Nagambie about 2:20pm on Tuesday, Victoria Police said.
A family member found the girl in the water but attempts at CPR to save her life were unsuccessful.
Meanwhile, a 17-year-old boy who died on Monday after being pulled from the water at a Melbourne beach has been remembered for his bright smile, wit and sporting talent.
Nick Maan drowned in water off a beach in Mordialloc in Melbourne's south-east on Boxing Day afternoon.
He was about to start year 12 and join the Gippsland Power football team, his father told Nine News.
"Nick put his life into football," Maan Maan said.
"He was a kind person, a hardworking son."
Anyieth Maan described her nephew as a "gentle giant" who helped raise his siblings.
"He looked after the little ones when mum was at work, and dad was at work," she said.
"He was a great role model."
Nick's sister, Teresa Maan, said her brother was "incredibly good-hearted".
"He took care of me," she said.
"He had several friends, who loved him so much."
Nick was a student at Lakeside College in Pakenham in Melbourne's south east.
The school's principal, Thomas Brennen, said in a statement that Nick's death "hits us at our deepest level."
"Nick joined Lakeside College in 2018 as a Year 7 student and will be remembered for his bright smile, deep thinking, wonderful sense of humour and of course, his sporting prowess," he said.
"As a small school community, we will feel his loss deeply. The college is supporting Nick's family at this most traumatic time.
"The college community will gather over the coming days to support each other, seek comfort in our Christian faith and share our memories of Nick."
Also on Monday, a 37-year-old man died in Ebden, in north-east Victoria, after following his dog into the water at Lake Hume.
Police said he may have suffered a medical episode.
On Christmas Day, a 19-year-old man also died while bodysurfing with friends where the Cumberland River meets the ocean in Lorne along the Great Ocean Road.
'These were young people with so much life ahead of them'
Kane Treloar, the director of lifesaving services at Life Saving Victoria, said losing a family member at this time of year was "absolutely heartbreaking".
"These were young people with so much life ahead of them. Every drowning is a tragedy, but especially when we're talking about young people," he said.
"We're urging everyone, with only a few days left in this main holiday period, to please show caution.
"Respect the water and make sure we're making good decisions around water so we don't have further tragedy."
Young girls rescued by police at St Kilda beach
On Tuesday morning, four people were rescued after their boat overturned at Barwon Heads on the Bellarine Peninsula, with two of them sustaining minor injuries.
Two sisters, aged 10 and 11, were also saved by police and a bystander from the water in St Kilda on Monday night.
Mounted officers were patrolling the beach when a member of the public alerted them that two girls were in trouble in the water, Acting Sergeant Samantha Christian said.
"We rode down to the water's edge and made the quick decision that Emma and I would hop off because they were in danger," she said.
She said a strong current was pulling the girls beneath the pier.
"We saw them waving then they disappeared," she said.
Leading Senior Constable Emma Sharp said a bystander was able to rescue one girl, then she and Acting Sergeant Christian swam 25 to 30 metres to get the other.
The pair grabbed the girl, who was able to follow instructions and kick the water to help them escape the current.
Acting Sergeant Christian said the girls were "in shock" but uninjured, and were reunited with their mum on the shore.
"It was such a relief because it was very hectic in the water," she said.
Mr Treloar said swimming around piers and thick structures was always dangerous because they could create strong rip currents.
"Being out there that late in the day, when the lifeguards have gone home for the day, sometime that signals it's time for you to go home as well," he said.
Since Christmas Day, lifesavers and lifeguards have performed 88 rescues across Victoria.
Authorities urge caution as hot weather continues
Life Saving Victoria (LSV) said there had been 93 rescues from water across Victoria since Christmas Day, including 50 rescues on December 27 alone.
LSV said there were almost 400,000 people at patrolled beaches yesterday, and lifesavers performed almost 15,000 preventative actions.
The Bureau of Meteorology said the worst of the heatwave gripping Victoria would pass today, with a cool change hitting Melbourne at about midday.
Melbourne recorded its hottest day of the year on Tuesday, reaching 37.2 C in the city, surpassing the previous high of 37.1 C on New Year’s Day.
Ballarat, Horsham and Wangaratta also had their hottest day of the year, while parts of north-west Victoria reached almost 41 C.
Mr Treloar said Life Saving Victoria was doing all it could to prepare.
"There'll be hundreds of volunteer lifeguards on duty," he said.
"Our drones will be out looking for dangers in the water, and of course the Westpac lifesaver helicopters will be flying right across the state from Barwon Heads to Moorabbin."
Mr Treloar said water was always unpredictable and urged beachgoers to swim between the red and yellow flags, and to swim with a friend where possible.
Ambulance Victoria has recorded an increase in demand due to the hot weather.
Executive director of Ambulance Victoria Anthony Carlyon said last night their workload was up by 13 per cent on normal volume.
"We know that heat kills more Australians than any other natural disaster," he said.
"Make sure you hydrate yourself … stay out of the sun … check in on your elderly neighbours, friends, family … and most importantly never leave kids in cars.
"Please get in with your GP, remember [to contact] nurse on call for minor issues and save triple-0 for emergencies."