I'm using

=iif(Weekday(Fields!Date.Value)=1 OR Weekday(Fields!Date.Value)=7 ,"red", "Blue")

The expression you posted is doing the same thing.

Is there a way I can get the value of the column when I have no data for that cell?

Is there a different way to set the color that affects the entire column instead of doing all the cells individually?

Thanks