Here is a little more data to think about.

http://www.calfishing.com/dc/user_files/7189-hour.gif

Unfortunately it's not really statistically significant enough to draw strong conclusions, but there are points of interest.

One consistent big fish bite for me across the years has been first and last light, meaning the hour after the sun has come over the horizon and the hour before it sinks below again. It's quite common for there to be a flurry of activity at this time which instantly shuts off the minute the sun is off the water. You can see this suggested in the graph in the 7-8AM. Less so in the evening, but I expect that's because I fish less during that time.

The only theory that makes sense to explain this phenomenon is underwater shadows. The lower the sun is in the skyline, the larger and longer the underwater shadows cast by it will be. I think these shadows provide cover that bass use to ambush prey.