Cedric, realized, with a sort of start, that Hermione had grown another inch. He realized, because the top of her hair, which used to reach just below his chin, brushed into his mouth when he went to hug her. Well, to be completely fair, Hermione's hair reacted in combination magic and humidity. In other words, when she was right pissed, her hair would bunch up in a mess of curls and frizz that was semi-sentient. At the moment, however, she was not frustrated nor angry, riding off an intellectual high of a nice discussion of the merits of becoming animagi.
He was just escorting her down to the dungeons on his free-period- the Hufflepuff dormitories weren't too far off, and just before they entered the corridor for the Potions lab, they made their goodbyes. The hug wasn't a gross overzealous display of affection, but neither felt comfortable being even marginally affectionate with Professor Snape hovering directly over them. The small growth made Cedric smile, a flash of affection for the thirteen-year-old that was steadily catching up to him physically.
Emotionally, intellectually, Hermione was already there.