Look how perfect that is! 7 days a week, multiplied times 4 weeks = 28 days, which is the number of days in February. This only happens the when the stars are aligned correctly, the last time being 11 years ago in February 1998. And previous to that is was another 11 years, in 1987.
PS: If you have some time to burn I recommend reading about calendars on Wikipedia, especially the Gregorian calendar. It's probably the best named calendar ever.
Here we go
2 weeks ago