Luckily, it can Mega Evolve now, and it still retains the same types.
Its X form loses the weakness to Water, retains both Ground and Rock, and gains one to Dragon.
While weak to Fire, Poison, Ice and Flying types.
Disclamer 2: All Pokemon names and locations contain a hyperlink to their pages.
They are also weak against fairy types, though this one seems to be the more head-scratching weakness of the bunch since there's no official or clear-cut reason for it.
Currently, he's also writing his second novel while actively working to get his first one published.