Basil had thought Hogwarts was already cold enough in November.
But when he woke from a dream one day in December,
Hogwarts had changed completely.
Outside the castle, everything had turned into a vast expanse of white.
The snow on the ground was several feet deep, and the lake had frozen into solid ice.
Inside the castle, only the common rooms and the Great Hall had roaring fires.
Everywhere else—whether the corridors swept by bone-chilling drafts or the classrooms whose windowpanes rattled under the bitter wind—was far from warm.
As a result, the castle was shrouded in smoke for a while.
The sudden drop in temperature had caused colds to spread among the students.
Matron Madam Pomfrey's Pepperup Potion had an immediate effect on colds.
It was very useful. One moment, someone would be listless and dripping with snot; after drinking it, they would perk up at once.
The consequence, however, was that smoke would keep pouring from their ears for several hours.
So for the next while, everyone obediently changed into fur-lined cloaks. Unless necessary, they hardly left their common rooms, or simply stayed in the Great Hall all day.
But there were always exceptions.
The adventure-loving Gryffindor students were not afraid of catching colds.
Whenever they had time, they held snowball fights outside the castle.
Fred and George were particularly outstanding among them.
They used magic to make snowballs, teased passing students, and chased after them while pelting them.
Unfortunately, Quirrell's teaching standards were no longer so terrible, so the two of them had not chased him around with enchanted snowballs aimed at the back of his head.
Voldemort's face was spared disaster.
Basil, the ever-helpful rainmaker, could not stand seeing Voldemort being neglected.
So when Quirrell passed by one time, a snowball inexplicably struck the back of