JK Rowling does not state that Harry is tall. She also does not state that he is short. He is though shorter than Ron and taller than Hermione as states in chapter The Seven Potters in Harry Potter and the Deathly Hallows.
Tall enough.
He is 6'1 feet tall.
Harry Newsome is 6'.
Harry Pavlidis is 6'.
Harry Gilmer is 6'.
Harry Gribbon is 6'.
Harry Cording is 6'.
Harry Carey is 6'.
Harry Frith is 6'.
Harry Styles is 5'11"
He is 6'1 feet tall.
Harry Andrews is 6' 2".