Residents are being warned about the dangers of going for a swim in rivers or the sea to cool down in the hot weather.
Rescuers say there are unpredictable currents or items under the water which could make swimming potentially dangerous.
The warning comes after the Tynemouth Volunteer Life Brigade (TVLB) were called to the river Tyne near Howdon on Tuesday, July 22, just before 6.30pm.
Two men decided to swim across the river from Jarrow, but while one turned back and returned to the south shore, the other continued.
When he arrived at the Howdon side, he was given safety advice from TVLB members before heading back to Jarrow.
But officials at the TVLB say the incident could have ended in disaster and urged people to consider other ways to keep cool in the heat.
TVLB captain Dave Bell said: “This callout occurred at the end of a hot, sunny afternoon when a cooling swim seemed like a good idea.
“However, TVLB would like to emphasis that the river Tyne, even on a hot sunny afternoon, is still a very dangerous place to swim, with unpredictable currents, cold water and submerged items all combining to increase the risk to the swimmer.
“On this occasion the young man was lucky and successfully completed the swim, unlike recent events where others have not been so lucky.”
New figures released by the RNLI show that 29 people accidentally lost their lives around the north of England coast last year – the highest number in four years.
The number of near-misses was even higher, with 52 lives being saved by lifeboat crews and lifeguards.
Now the charity is launching a major drowning awareness campaign, ‘Respect the Water’, warning people to stay safe this summer.
Michael Avril, the RNLI’s community incident reduction manager for the north of England, said: “With more people losing their lives at the coast each year than are killed in cycling accidents, we’re trying to make people, particularly men, realise that they are at risk from drowning if they don’t follow some basic but important safety advice.
“Of course we want people to go to the coast and enjoy it but we want people to understand there are risks, and that they should not underestimate the power of the sea.”
Despite warm summer air temperatures, the UK sea temperature is cold enough year-round to trigger cold water shock – the average UK sea temperature is just 12c , but cold water shock can set in at any temperature below 15c.
It causes uncontrollable gasping, which draws water into the lungs and can lead to drowning.
Other common factors are rip currents and fatigue.
Mr Avril added: “Our key advice is to choose a lifeguarded beach and swim between the red and yellow flags, where you’ll have professional lifeguards looking out for you.
“If you want a few drinks in the sun on the beach, remember that alcohol and water don’t mix, so drink after swimming, not before.
“Remember that, despite warm air temperatures, the UK sea temperature is cold enough year-round to trigger cold water shock, so acclimatise gradually in shallow water.”