Summer is here, school will soon be out and Canada’s short swimming season will be in full swing.

But first, a warning: Swimming lessons for young children can result in parents who are too confident about youngsters’ ability to keep from drowning, says a child safety expert.

As a child under five accumulates swimming skills, parents begin to assume their child is not likely to drown and that they don’t need to as closely supervise him or her, says Barbara Morrongiello, a psychology professor at the University of Guelph who holds a Canada Research Chair in child and youth injury prevention.

She and colleagues spent eight months studying the beliefs of parents whose children were taking swimming lessons. Turns out, parents overestimated their child’s swimming skills when compared with the assessment of instructors.

Swimming lessons for very young children “build a comfort level in the water,” and a confidence in children that “they can manage a scary situation like water, if you will, a pool or a lake or what have you,” she told CTV News Channel on Wednesday.

But that doesn’t mean a child will know what to do in a drowning situation, such as when they panic after falling in with clothes and shoes that make them heavier, or they’ve drifted into water that is over their heads. Other factors in drownings can include fatigue, muscle cramping, injury, and the effects of cold water.

“Another thing that parents don’t always realize is that drowning happens quickly and silently. It’s not often the case that children are able to call for help or splash around. Once their lungs fill with water, they’re going down and they’re going down quickly.”

Parents often aren’t watching their children as carefully and continuously as they need to be, said Morrongiello. A tragedy can happen in seconds.

“We always overestimate how much we are supervising and we underestimate how long since we’ve last seen the child.”

The Canadian Paediatric Society (CPS) (http://www.caringforkids.cps.ca/handouts/water_safety) says there is no evidence that swimming lessons prevent drowning in children under four because they just aren’t old enough to manage survival skills or to learn about drowning prevention. In fact, research has found that about two-thirds of those of any age who drown are considered to be good swimmers.

Drowning is the second most common cause of death for children under five years of age in Canada, according to the CPS. According to the Lifesaving Society, 35 per cent of all drownings happen in July and August.

Some safety tips from the Canadian Pediatric Society:

• Babies who can’t sit without support and are too young to wear a portable flotation device (PFD) should be held by an adult at all times.

• Toddlers should always be within arm’s reach of a watchful adult when they are in or around water. This includes pools, bathtubs, and beaches, and other water sources.

• Swimming lessons are a great opportunity for families to participate in fun activities that contribute to a healthy lifestyle. But on their own, they will not protect or prevent a child from drowning.

• All children should be supervised by an adult when they are in or around water and should never be left alone in a pool or bathtub, even for a moment.

• The Lifesaving Society recommends a supervision ratio of at least 1 adult for every 2 young children, and 1 adult for every baby.