If Jenny hops on, she can tell us for sure, but I'm fairly certain there is no set schedule for his journal. It would appear that if he's inspired, has something to say, and has the time, he writes, but as far as I can tell, it's never been on a fixed schedule, and certainly not monthly basis.

Compared to a lot of other skaters who might not update their journals more than twice a year, if that, Johnny is quite prolific in his updates. As a grace note said, Johnny's fans are very lucky in that regard.