Do I need a comma after the word "later" when used as an introductory adverb in a sentence? take the example"

Later in September 2015 I discovered my error.

Should there be a comma after 2015 since "later in September 2015" is a dependent clause or adverbial clause?

Please help

edward

September rolled round, and the first winds of autumn......when I first met him at his birthday party on the 6th ... Later in September, I discovered...

Later, in September 2015, I discovered...