Yes, it is very much possible.
So go to the Dashboard
in your Analytics
Tab in the Firebase Console.
1-day, 7-day, and 30-day active users are plotted over time. Summary
values at right show the number of active users as of the last day of
the date range.
So from the drop-down menu select This Week
and you can see on which day you have the most number of Active Users
Daily, Weekly and Monthly. It also shows the drop/increase rate from the previous date.
You can also add your custom filters for the same.
EDIT-
In the Analytics Tab go to StreamView
where you can check the Users/Events
in the last 30 minutes with the location.This might come handy for you if you check this tab on the day you expect the maximum number of users.