Other than mid summer when the Plankton Bloom can cut it down a bit -
visibility is normally 10-20 metres or better. April is the clearest
(and coldest)

A couple of weeks ago it was about 5-10 metres but that was after a
long period of forge 6-8 SE winds. Some of the sites were still about
20 metres.

Last October you could see the bottom at 35 metres clearly from the
buoy.