Simply put, your boss will like you more.
Research from the Michael G. Foster School of Business at the University of Washington suggests that employees who get into the office early are generally perceived by their managers as more conscientious and receive higher performance ratings than employees who arrive later.
And it doesn't matter if those who get in later stay later, too.
In the Harvard Business Review, the paper authors write:
"[I]n three separate studies, we found evidence of a natural stereotype at work: Compared to people who choose to work earlier in the day, people who choose to work later in the day are implicitly assumed to be less conscientious and less effective in their jobs."
The one caveat? If your boss is a night owl, they probably won't judge you as harshly for showing up on the later side.