Low tide at Washington Oaks is about 24 minutes off from the the tide reports given for the St. Augustine pier. Make sure to get there at least an hour or two before low tide as once it hits low tide it begins to rise quickly. The water temps are warmer now than when I went last month so there should be more activity on the rocks. When I went in March the water temp was only in the 60's. Good luck and have fun!
You will have to tell me what you think when you get back.