If you need to get last day of the month (current month or any other) on SQL Server, use in-built function EOMONTH.
SELECT EOMONTH(GETDATE()) SELECT EOMONTH('2011-06-11')
In examples above, first select statement will give you current month’s last day, and second statement will give you last day of July in 2011.
You can then combine this with DATENAME function to get day of the week name.
SELECT DATENAME(dw, EOMONTH(GETDATE())) SELECT DATENAME(dw, EOMONTH('2011-06-11'))
First select statement returns Saturday as last day of the current month, and second statement returns Thursday as last day of the July 2011.