You can go to NOAA site and they have an observed tide versus predicted tide product, that shows you the actual tides that week versus what was predicted that allows you to see any patterns for that time period.
My general Copahee rule of thumb is I will probably be dragging an hour and a half on either side of low. Look at the tide prediction in the charts, but also check what the actual observed tides have been doing, as the 2 can vary considerably!