Spirit Lake is one of the most frustrating lakes to fish, summer or winter. There are plenty of fish in the lake, it's big and you have to find them. And the fish are not necessarily under the cities of shanties that pop up on the ice. Those are sheeple. People who plant themselves on the deepest holes and then other people move in because if they are there they must be catching something. Along the Sunset beach side a huge city developed last Saturday. Not sure if anyone caught much.
I would avoid the big groups of people, unless you see people on buckets pulling in fish. Spread out away from the groups.
Day to day and Week to week the fish move around...I get so mad going there but some days I love it and that keeps me going back.
