Reading a tide table properly
Every number on a tide table is a prediction. The published height is what the harmonic model expects given the moon, the sun and a century of local observation, and the water does not consult it. A hard northerly will hold half a metre out of a spring high and a deep low pressure system will push the same amount back in. The practical habit is to read the table for the shape of the day and read the wall gauge for the number you actually act on.