Vacay.ca believes that answer is Basin Head, located (N 46 22.853 W 62 06.590) on the eastern end of Prince Edward Island, roughly a 1 hour and 15 minute drive from Charlottetown. This title of #1 has had the local media buzzing. Here is what Vacay had to say:
For reasons scientists are still trying to figure out, this beach makes a strange swishing sound whenever the wind swirls or when a visitor walks on it. Tourism officials on Prince Edward Island suggest the reason may be because of the texture and consistency of the quartz sand. Nevertheless, the sound is a unique feature of a beach that has some of the warmest waters north of Florida. In summer, the water temperature will top 21 Celsius degrees (70 Fahrenheit) at Singing Sands and other sandy spots on PEI, which has more than 800 kilometres of beaches to explore.
Why This Beach Rocks: Some of the warmest waters in the northern hemisphere. The supervised beach is in a day-use (summer) park that has a play area, food, washroom, shower facilities, and the Basin Head Fisheries Museum.
Today’s Image – Singing Sands at Basin Head Beach
I have not yet made the drive to Basin Head this summer, but here is an image from the archives of this clear water beach on a foggy day.