The third Monday in February is always Presidents Day. That means it must occur somewhere between February 15 and 21. We think of it as a combination of the birthdays of Washington and Lincoln.

But--this is interesting--their birthdays don't fall in that span. Washington was born on either February 11 (according to the old-style Julian calendar, still being used) or February 22 (the newly-adopted Gregorian calendar). Lincoln's birthday is February 12. Two other presidents were born in February: William Henry Harrison on February 6, and Ronald Reagan on February 9. So Presidents Day will never occur on an actual president's birthday.