@faulduff,
In JavaScript, date object can be created in 4 ways. new Date()
, new Date(year, month, day, hours, minutes, seconds, milliseconds)
, new Date(milliseconds)
, new Date(date string)
.
In your case i.e new Date(year, month, day)
, month counts from 0 to 11 i.e. 0 corresponds to January and 11 corresponds to December. Changing the month according to JavaScript date-object should work fine in your case.
For different JavaScript date formats please refer this article.
Please take a look at this JSFiddle for a working example with sample code.

—
Vishwas R
Team CanvasJS