Group by month is very simple task to achieve in SharePoint List View.
Simply create one computed column with formula:
Now Group by that view by this field to view in particular order ascending or descending.
So to achieve that add following formula:
=REPT(" ",13-MONTH([Start Time]))&TEXT([Start Time],"mmmm")
What’s the trick? To force the order, we are adding a bunch of white spaces before the month name. The calculated Month actually contains the following values (each _ represents a white space):
Now, why don’t we see these spaces on the Web page? What makes the magic work is that when you insert multiple spaces in a Web page, the html specification says that
user agents should collapse input white space sequences