This function is only available if the Analysis AddIn is installed.
Syntax:
WEEKSINYEAR(date)
returns the number of weeks in the year in which date lies.
A week is considered to start on Monday, and is considered to be in the year if most of its days are in that year.
Example:
WEEKSINYEAR("2010-02-14")
returns 52, the number of weeks in 2010.
WEEKSINYEAR("2009-02-14")
returns 53, the number of weeks in 2009. In 2009, both 1st January and 31st December fall on a Thursday; the weeks containing 1st January and 31st December both have most of their days in 2009, and therefore both are counted.
Issues:
WEEKSINYEAR is not part of the ODFF international standard, and should not be regarded as portable. It is not available in Excel.