Every winter, Sweden's tourism industry is a bit special. Tourists who spend the night here account for more than 90% of the total number of tourists, and it is often the next morning.

A, tourists spend the night here to watch the extreme night phenomenon, so it does not meet the meaning of the question;

B, tourists spend the night here not for the forest party, but to watch the extreme night phenomenon, so it does not meet the meaning of the question;

C, Sweden has a high latitude, and it is correct to observe the extreme night phenomenon here at night;

D, the winter half year is not only 65438+February 25th, but also tourists spend the night here to watch the extreme night phenomenon, not to participate in Christmas activities, so it doesn't meet the question.

So choose: C.