Yeah it is - the obvious change is overall temp warming (global), not that it feels like it this year.
The busy day tickets see more pressure when conditions are low pressure, last trip I had boilies washing into my bank so too much is going in big time, could the general warming effect the water quality with so much un-eaten bait (pollution) in the lake?
Saying that what you said about the fish showing less in favorable conditions is true to my recent experiences, does low pressure affect oxygen levels?