The sun can definitely play a role in northern pike fishing. The sun doesn’t always make the fishing better or worse. Pike are opportunistic feeders, so if you can find them and present them with a bait that interests them, you will probably get plenty of bites. In darker water, the sun will actually help pike see your lures and baits better. They are sight feeders so the sun will actually help to improve the bite quite a bit when fishing in darker water. In clear water, the sun will help pike see much farther through the water, which allows them to see your baits from greater distances, but also makes them a little more spooky at times.
During the summer and fall, pike will usually be found in deeper water once the sun gets high in the sky. These fish are still willing to bite, but you may have to switch over to live baits and slow down your presentations.