One way:

Assuming A2 is the active cell

CF1: Formula is =WEEKDAY(A2,3))4
Format1: Grey

CF2: <your current CF
....

In article ,
"Edgar Thoemmes" wrote:

Hi

I have a holiday planner which is set up with days of month in range c3:ag3.
Name of the staff in b4:b7. Staff will update this with either a 'F'(full
day) or 'H'(half day).

I have all months on the same sheet so feb dates will start in range
c11:ag11 and march will start in c17:ag17 etc

I have set up conditional formatting to highlight the cell depending on the
entry made but I would like if possible is to highlight all cells which are
weekends in grey. Can anyone advise how to do this?

TIA