Hi,

With ANY date in A1, the following will return TRUE if the NEXT Saturday
is the
LAST Saturday in the month; otherwise it will return FALSE.
...
If you do not want to add the ATP, then use this formula instead:

=AND((DATE(YEAR(A1),MONTH(A1)+1,0)-WEEKDAY(
DATE(YEAR(A1),MONTH(A1)+1,0))-A1)<=7,(DATE(
YEAR(A1),MONTH(A1)+1,0)-WEEKDAY(DATE(
YEAR(A1),MONTH(A1)+1,0))-A1)0)

Also :

=DAY(A1+15-WEEKDAY(A1-6))<8

Which is another way of saying the if NEXT saturday of A1 date is the last
saturday of the month, the NEXT one (7 days later) will be in the first 7
days (<8) of next month.

Regards,

Daniel M.