Does cell A1 fall between X & Y dates and Splitting year into 13 periods of four weeks

Hi I've included a workbook which hopefully will explain this better but here goes:
I need to check a date in a cell to see if it falls in a certain period of the year.
The year is split into 13 periods of 4 weeks each starting on 15/03/15 this year.
So for example today (28/03/15) is Period 2

Please if anyone can help I'd really appreciate it.

Thanks,

Kevin.