Weather:

Water temps:

• Cocoa Beach Pier sea temperatures peak in the range 28 to 30°C (82 to 86°F) on around the 26th of July and are at their minimum on about the 10th of February, in the range 20 to 23°C (68 to 73°F). Year round warm sea temperatures at Cocoa Beach Pier climb to their highest in the fourth week of July.  (According to Surf-forecast.com)
  

Average Air Temps:

... and a note about weather - according the owners:

• Winter:  Can get quite cool (for short periods of time) but average is 70 to 80 during the day
• Spring: Beautiful
• Summer:  It can be hot and muggy in Florida.  However, on the ocean - at the beach (aka at one of our condo's) - it feels a solid 10 to 15 degrees cooler than inland. 
• Fall: Beautiful