Winter months are better for me, February being best last year. In reality though, that has to do with temperature and how much rain, so it could easily be drastically different this year. January was good last year but can say the same this year so far.
Like APB said depends on how you want to fish for them. I catch a lot during summer pulling live bait but 5 on bass rods casting in winter is far more fun than 10 on down rods to me.
I don't think anyone will argue though, that bigger fish are easier to come by during the winter.