The middle tide zone, also known as the midlittoral zone, doesn't have a fixed depth. Its boundaries are defined by the tides, specifically:

* Upper limit: The area that is only submerged during the highest high tides (spring tides).

* Lower limit: The area that is only exposed during the lowest low tides (neap tides).

Therefore, the depth of the middle tide zone varies significantly depending on location, time of year, and the specific tidal cycle.

Here are some general points:

* It is typically shallower than the lower intertidal zone.

* It can be as shallow as a few inches or as deep as several feet.

* The actual depth can change dramatically over the course of a day.

For a more precise understanding of the middle tide zone in a particular location, you would need to consult tide tables and consider the local topography.