10 days ago I went to Island Beach State Park in NJ right around low tide. The waves were a pretty good size and the water was warm enough to get used to (I still thought it was cold though). I was able to play in the surf for a half-hour and only got out because I was getting battered by the waves. Exactly 1 week later (last Thursday), I went back to the same spot. It was approaching high tide this time, but the waves were very small and gentle. I understand that the ocean floor probably played a part in this, however, the biggest difference was how COLD the water was. I stood for 20 minutes in thigh-high water and my feet were so cold they ached. Even my leg muscles were starting to cramp up. Does high tide bring colder water? Smaller waves?

well i think its cause there is more water to heat up with the same amount of sun, maybs?