Year 1 - Hermione went home for Christmas.
‘You will keep looking while I’m away, won’t you?’ said Hermione. ‘And send me an owl if you find anything.’
‘And you could ask your parents if they know who Flamel is,’ said Ron. ‘It’d be safe to ask them.’
‘Very safe, as they’re both dentists,’ said Hermione.
Harry Potter and the Philosopher's Stone
Year 2 - Hermione stayed in order to use the Polyjuice potion to try to weasel a confession out of Malfoy.
In the second week of December Professor McGonagall came around as usual, collecting names of those who would be staying at school for Christmas. Harry, Ron and Hermione signed her list; they had heard that Malfoy was staying, which struck them as very suspicious. The holidays would be the perfect time to use the Polyjuice Potion and try to worm a confession out of him.
Harry Potter and the Chamber of Secrets
Year 3 - Hermione stayed, ostensibly to study, but in reality because Harry was unwell.
Both Ron and Hermione had decided to remain at Hogwarts, and though Ron said it was because he couldn’t stand two weeks with Percy, and Hermione insisted she needed to use the library, Harry wasn’t fooled; they were doing it to keep him company, and he was very grateful.
Harry Potter and the Prisoner of Azkaban
Year 4 - Hermione stayed in order to attend the Yule Ball.
Harry had never known so many people to put their names down to stay at Hogwarts for Christmas; he always did, of course, because the alternative was usually going back to Privet Drive, but he had always been very much in the minority before now. This year, however, everyone in the fourth year and above seemed to be staying, and they all seemed to Harry to be obsessed with the coming ball – or, at least, all the girls were, and it was amazing how many girls Hogwarts suddenly seemed to hold; he had never quite noticed that before. Girls giggling and whispering in the corridors, girls shrieking with laughter as boys passed them, girls excitedly comparing notes on what they were going to wear on Christmas night …
Harry Potter and the Goblet of Fire
Year 5 - Hermione claimed to her parents that she was going to stay at Hogwarts to study, but in fact absconded from the school to go to Grimmauld Place.
‘What are you doing here?’ Harry asked her, pulling open the door as Buckbeak resumed his scratching at the straw-strewn floor for any fragments of rat he may have dropped. ‘I thought you were skiing with your mum and dad?’
‘Well, to tell the truth, skiing’s not really my thing,’ said Hermione. ‘So, I’ve come here for Christmas.’ There was snow in her hair and her face was pink with cold. ‘But don’t tell Ron. I told him skiing’s really good because he kept laughing so much. Mum and Dad are a bit disappointed, but I’ve told them that everyone who is serious about the exams is staying at Hogwarts to study. They want me to do well, they’ll understand. Anyway,’ she said briskly, ‘let’s go to your bedroom, Ron’s mum has lit a fire in there and she’s sent up sandwiches.’ Harry followed her back to the second floor. When he entered the bedroom, he was rather surprised to see both Ron and Ginny waiting for them, sitting on Ron’s bed.
‘I came on the Knight Bus,’ said Hermione airily, pulling off her jacket before Harry had time to speak. ‘Dumbledore told me what had happened yesterday morning, but I had to wait for term to end officially before setting off. Umbridge is already livid that you lot disappeared right under her nose, even though Dumbledore told her Mr Weasley was in St Mungo’s and he’d given you all permission to visit. So …’
Harry Potter and the Order of the Phoenix
Year 6 - Hermione went home for Christmas.
‘So how was your Christmas?’
‘Oh, fine,’ she shrugged. ‘Nothing special. How was it at Won-Won’s?’
‘I’ll tell you in a minute,’ said Harry. ‘Look, Hermione, can’t you –?’
Harry Potter and the Half-Blood Prince
Year 7 - Hermione and Harry were on the run and spent Christmas in hiding.
‘Harry, I think it’s Christmas Eve!’ said Hermione.
He had lost track of the date; they had not seen a newspaper for weeks.
Harry Potter and the Deathly Hallows