I'm a fair weather boater so I don't get in the water without a wet suit until the air temperature is in the 80's and the water temperature is above 60 degrees. If your playing in the water it is still really cold but getting pulled behind the boat isn't too bad if you can get them out of the water quickly. Unfortunately, kids don't have much meat on them and they get cold rather easily. My kid wore a shortie wet suit through the early summer. You want the kids to be comfortable or you will start hearing some whining. The wet suits aren't too bad in price and I still have my daughter's old ones for others to use.