The information below is official vacation policy of the university, which you should read. Please let me know if you are going away for an extended period so the group can plan accordingly, and put the travel days in a Slite document in the base of your channel.
In terms of the winter period, most research activity at the university will return to business as usual by the middle of January in time for Wintersession. Graduate students and postdoctoral researchers are paid to pursue research as a full-time commitment (i.e. they are considered more as employees in this capacity). In other words, graduate students and postdoctoral researchers are expected to carry out their research activities during the summer and between semesters (i.e. during semester "breaks").
The vacation policy for graduate students and postdoctoral researchers is quite different than when one is an undergraduate student. Official university policies regarding vacation days can be found below.
The above information is not relevant for undergraduate researchers who are only expected to work in the group during the semester unless otherwise stated, as they are generally pursuing research for credit.