I just don't like it - a circle implies continuity, so it's weird to have a 12-hour jump hidden inside the graphic. And, as noted by others, we don't have any background for reading a clock that is part AM and part PM.

You could make it more readable, though still disturbing, by adding "Noon" as a label above the 12, maybe with a heavy line .

You could do a circle that showed the whole 24 hours, with half of it (plus 0, 1, or two hours) shown as closed. That's clearest, but wastes half the circle, of course.

It would be nice to avoid having separate charts for weekdays, Saturday, and Sunday. If you did concentric circles for the three patterns, that might make it look more chart-like and less clock-like, which would avoid the confusion.

How about three concentric 24-hour arcs - just the part of the 24-hour clock that the store is open (the rest of the circle omitted)?