Humberside Fire and Rescue Service is reminding the public that cooling off in rivers, lakes, docks or reservoirs can be fatal.
Drowning in the UK is one of the leading causes of accidental death.
Each year more than 300 people drown after tripping, falling or just by underestimating the risks associated with being near water.
Humberside’s service area includes 70km of East Yorkshire coastline and around 130km of Humber Estuary banks which may not be that appealing for swimmers, but can catch out anglers or dog walkers in the dangerous and unpredictable mud and tides.
HFRS public safety group manager Steve Duffield said: “Any open water can be deadly, especially at this time of year when the water temperature is still low despite the high outside temperature.
“I would urge the public to call 999 immediately if they see someone in trouble and to never enter the water themselves to try and save others – it often makes matters worse.
“I would urge those drinking alcohol in our town centres, often near the water’s edge, to be especially careful themselves and call for help if others get into difficulty.
“Those with young children should keep them supervised at all times.
“Sadly, it only takes a couple of seconds for a great day out in the sun to turn into a life threatening situation.”