View your users' recent sign-in
You can always see the hour when a user last signed in to their account - just check the Last signed in column on the Users page of the Admin console. The Last signed in timestamp is only updated once an hour, so the timestamp of a user who signed in after 9 AM won't refresh for later sign ins until after 10 AM.
Before a user signs in to their account for the first time, the column reads Never logged in. If a user has signed in during the last 24 hours, you'll see the time; otherwise, you will see the date.