Aerin,
Looking at the calendar now, on mobile, it looks to be responsive. Not the prettiest looking calendar, but functional. I must have had a issue with it a few months ago, but I can not remember what/why.
However, if you are open suggestions: it would be awesome if the interface on mobile was something like this https://kthornbloom.com/monthly/. So, that the tap targets could be larger, there would be only one tap target on one date, and clicking a date would bring up another view of all the events for that date. Another idea, would be to use DIV tags or possibly UL to build the calendar, then you could display a single date in a single row, allowing room for links to events. Just some ideas.
Cheers!
Ethan