Several people have asked me if this or that planner has monthly calendars. Personally I wish every planner did, but some don't. Luckily, there's a way to fix that.
Moleskine Templates (http://mymoleskine.moleskine.com/community/msk_templates.php) are free and just require you to log in (which is painless). They have monthly, weekly, and other templates available to print and stick into your planner or notebook of choice.
I did an experiment with the Moleskine monthly printables and taped them into the address booklet in the back of the 2013-2014 Moleskine Turntable planner that I reviewed here, which does not have monthly grid calendars (only the monthly columns). The result is pretty good.
I'm sure someone else could do a tidier job than I did. But, it solves the lack of monthly calendars.