I have same problem,
I’m using canvasjs charts on lots of my sites, but just noticed today that all of them is one month ahead somehow,
I just checked the data the chart was getting, and the time is correct.
 => Array
[totalweight] => 13842951
[time] => 2015, 05, 26, 15, 00
But the chart shows 2015, 06, 26, 15, 00
I tried sorting it as per brunberg posts, but didn’t work.