Currently the calendar format only allows seems to allow you to click through month by month. This is very cumbersome and would be better off if you were allowed to type the date if you need to jump ahead or go back a significant amount of time.
We actually found a solution to fix this on the portal, but I think it's sort of obvious that this should be built in to the product to have the localization straight from the box.
jQuery( this ).datepicker( "option", "firstDay", 1 );
It's based on jQuery UI doc:
We introduced a new date picker across the product a few months back (we missed notifying here). You can now choose the Year and Month on the date picker instead of having to navigate one month at a time. I hope this solves the usability issue you were facing. Let me know if this helps.
How about having the weeks starting on a Monday? At least in Sweden and most (all?) of Europe this is the format we use.