Lesley Burton-Zehr is planning to swim the 75 kilometres across Lake Huron on July 19-20, 2014.
The former competitive swimmer and lifeguard tried a similar swim last summer but had to postpone because of the potential of eight-foot waves.
Zehr is going to try the 40-hour swim again this summer, but the challenge this year may be really cold water.
The lake temperature is currently hovering near 5 C with ice still on some parts of the Great Lakes.
Zehr is doing the lake crossing to raise awareness of water safety.
She is trying to raise $50,000 to fund swimming lessons for Ontario kids through the SEALS Swim to Survive program.
Zehr has raised a little over $6,000 so far.
