She was planning to go skiing with her parents. Instead she chose to take the Knight Bus to Grimmauld Place to join Ron and Harry and the rest of the Weasley family when the term ended.
Hermione arrives at Grimmauld Place for the holidays
Date December 20th, 1995
Certainty Date based on real world calendar
Location in Canon OP23: Christmas on the Closed Ward
Type of Event Wizarding world