I make May the 4th warmest May in my DIYDIY Do It Yourself series that started in 1948. Its tight at the top, but May 2016 is still fractionally higher.
Global mean temperatures have started to show a bit more consistency in their rate of warming over the last month or so.
The current global increases are due in a large part to a sharp rise in temperatures in the subtropical northern hemisphere and not from the tropics. Having said that, increases in the north seemed to have peaked in early May.