Just a WAG is that it might be related to the narrow opening at the Straits of Gibraltar. Anything more (or else)???
I can’t think of anything else that would affect tides except wide and narrow channels or inlets. Maybe an orbital conjunction of the sun and moon?
Where the hell is Chronos these days??? 
Itr is almost a lake and not big compared to the oceans.
I found a pretty good discussion here.
Basically, the largest tides take place where (a) the basin has a resonant frequency of twice daily, like the frequency of the lunar tides; (b) where there is shallow water or a narrow inlet to concentrate the volume of water in one or two dimensions; © where there is no tidal node.
The Mediterranean is small enough that its resonant frequency is many times a day, not twice a day. The inlet is narrow enough that the ocean does not have a significant effect on this (and the Mediterranean’s native tides are too small for the inlet at Gibraltar to create big ones). I don’t think the Mediterranean is actually anywhere near a node, though.
The link in the page I linked to is out of date: here is the new one:
http://www.ssc.erc.msstate.edu/Tides2D/Global/Model/figures.html
Arrgh! wha’ppen? Moderator
Lake Superior has small tides, and I’m pretty sure the Mediterranean is considerably larger in surface area.
The Chesapeake Bay is a long body of wateer whci runs from N to S. If the mouth of the bay were closed off from the sea there would be no tides in the resulting lake as the width of the Bay is too narrow. The existing tiides are just the efect of the tide at the mouth of the bay. The existing tides are just waves generated at the mouth of the bay by the oceanic tides and which propagate up the bay.
Now imagine the bya if it was rotated 90 to the west. The wave which starts at the mouth of the Bay, as it travelled west, would be continually reinforced by the effect of the moon also traveling west. The result would be a huge tide on the Bay with the water sloshing back and forth between E and W.
Cite? I have lived all my life on Lake Michigan, and never noted a tide at all. Readings I’ve done in the past indicate any tide is too small to be measured, as the variation due to wind and currents alone mask it.
http://www.great-lakes.net/teach/chat/answers/100100_tides.html
This site backs this up. Lake Superior has maximum gravitational tides of 4 cm, which is a small enough amount to be covered up by weather changes.
Ach, you’re right, Qadgop. I should know better than to post a “fact” without checking it out first. The tide in Superior is about 1 inch; hardly of any consequence. The more significant level variation is called a seiche. Guess sailor’s first post was likely correct.
So much for high school geography…
OTOH you were right when you said 'I’m pretty sure the Mediterranean is considerably larger in surface area"_