Date and Time
Calculates the number of weeks of the year in which the date entered occurs.
Date is any date in the respective year. The Date parameter must be a valid date according to the locale settings of LibreOffice.
The number of weeks is defined as follows: a week that spans two years is added to the year in which most days of that week occur.
WEEKSINYEAR(A1) returns 53 if A1 contains 1970-02-17, a valid date for the year 1970.