Talk:Moons/@comment-10390252-20141229175949

So, six lunar months passed between Equestria Girls and Rainbow Rocks. It doesn't tell us how long that is but it does suggest that a lunar month in the Pony world is longer than on Earth. It's possible that their moon is a lot bigger than ours and, consequently, has a wider orbit.

If I was asked to make a bet, I'd say it's around eight weeks; it's also possible that the solar year on the Pony world is longer, possibly explaining how Season 4 could have started only one Summer Sun celebration after Luna's return.