Calculate exact day of week from RTC calendar

Hi,

I am working with the LaunchPad MSP-EXP430FR6989

I am trying to show the date on the screen with the format "SUNDAY 08H00" after entering the complete date (DDMMYY) with a keyboard.

I read some posts saying that the day of week (Calendar->DayOfWeek) is arbitrary, and it only changes after the RTC goes from 23:59:59 to 00:00:00. It seems there is no way of knowing the exact day of week (Monday, Tuesday, etc.) from a specific date.

Am I missing something or is it impossible to have this information?

Thank you.