You can find the specific dates for the academic year, such as semester start/end dates and holiday schedules, on the university registrar’s webpage:

https://www.stonybrook.edu/commcms/registrar/calendars/academic_calendars

Below are monthly reminders for PhD students:

Fall & Winter

A week before the Fall semester

Day 5 of Fall semester

Friday of week 2 of the Fall semester

November

End of Fall semester