I have a spreadsheet with lots of formulas and conditional formatting.
Currently If the cell is less than or equal to the cell above, the
conditional format sets the colour to white, so it is not displayed on
screen. This is because I have set all the formula in place for the full
year and do not want to display future months.

What I would like to do is change the conditional formatting, so that if the
current date is greater than or equal to the previous month end it will be
black, but otherwise it will be display as white.

For example, we are currently on 4th September, so my September cell would
still show white until we get to 30th September, when it will show black.
However, my August cell would have changed to black.

I appreciate that I will probably have to amend the date on each of the lines.