Prior to June 1st the water temperature on Lake Champlain is typically near or below 50F. At those temps, falling in the water without a PFD is a life threatening situation. Whether in your dinghy or on your boat, it is stongly recommended to wear your PFD at least until the water temps are consistently above 50F or more conservatively above 60F (if you care to jump in, you'll find 60F is still pretty darn cold and can become debilitating).
To check the current lake water temperature CLICK HERE
For your annual reminder regarding the dangers of Cold Water Immersion CLICK HERE