What clothes does Hermione find to wear?

Just the Invisibility Cloak

Hermione let out a cry of anguish.

Where her clothes should have been, only the Invisibility Cloak remained. Not only had her pyjamas gone, but so had the Marauders Map and worst of all her wand! Starting to panic, she rushed over to where the towels were kept; the basket was empty. A quick search of the room showed that there was nothing else for her to wear.

"Nooooo!" Hermione wailed, collapsing onto a toilet and burying her head in her hands. How, HOW, had this happened? Was Hogwarts so unspeakably cruel it would strand her with just a cloak? She surely would have noticed if someone had entered the room and taken her things.

She supposed she should be relieved that she still had the Invisibility Cloak. Not having anything at all would be mortifying!

Throwing the cloak around her shoulders, Hermione pulled up the hood and disappeared . Taking a deep breath, Hermione pushed open the door.

After six years at Hogwarts, Hermione knew her way around the school, so set off quickly towards the Grand Staircase.

If she had been cold in the bathroom, it was unbearable in the airy corridors. The cloak provided absolutely no warmth, with the cold air blowing up the hem and over her wet, naked body. Hermione's wet feet slapped loudly on the floor, the cold stone doing its best to sap any of the remaining heat out of her. She cradled her breasts with one hand as she held the cloak with the other.

Hermione peered around every corner and listened as hard as she could for approaching footsteps, and prayed that she would make it back without meeting anyone.

Her one saving grace was that if she did, they couldn't see her...as long as they didn't walk into her.