Each Canvas course has a "time zone" setting that you can set in the "Settings Tool". When an instructor sets times for events (Assignments/Quizzes/Discussions/Calendar) in the Canvas, those times are based on the time zone that is set for the course.

This primarily affects the instructor when creating things that have a date/time attached, so if an instructor creates an event at "2pm", that time is in the time zone set for the course.

Students also have their own personal time zone settings under their profile, and times shown in their view of Canvas are translated into the student's personal time zone from whatever time zone is set for the course, so a 2pm event from a class in the Eastern time zone will show as 1pm for students who have their own personal time zone set to Central time.

If your students are accessing your Canvas course site from a different time zone, it is important that they set their personal time zone under their profile. If they don't, they will see the due date/time as it is set for the Course time zone.

Instructions for students to change their personal time zone in Canvas are here:

 Student - How do I set my local time zone in my user account?

NOTE: The default time zone for all Tufts Canvas course sites and all Tufts Canvas accounts is Eastern Time (US & Canada)