The Grand Bend's city beach is good on its own, but it maybe worth checking the Pinery's South beach as well (even though the Pinery is a provincial park with paid access).

• Lambton Shores Web Cams Blue Flag Beach, North Beach (Rotary Stage), Grand Bend Pier
• Web cam at Grand Bend Yacht Club
• Buoy 45149 [RSS] [HTML] at NDBC NOAA
• Grand Bend Full Weather Forecast at weather.ca
   
  If there are any surf cams in the area, please be kind to share.
  Your help will be greatly appreciated! :-)

Lake Ontario water temperature near Grand Bend, ON