Is there a formula to change the colour of a cell, based on todays date?

Question

I have a spreadsheet in Google Docs which has a new column for each day, the header being the date it was filled out.

I want to to set the background colour as grey for every column which has a header/date that comes before today.

(Note: the cells I want to set the background colour for do not contain a date. It's only the header of the column)

Is this possible?

Answer 1

Not sure if this is applicable as i do not use Google Docs but it works in excel.

Left column                  right column

Tuesday, July 24, 2012       =IF(B1<B3,1,0)
Wednesday, July 25, 2012     =IF(B2<B3,1,0)
Thursday, July 26, 2012      =IF(B3<B3,1,0)

Result:

Left column                  right column

Tuesday, July 24, 2012       1
Wednesday, July 25, 2012     1
Thursday, July 26, 2012      0

Now apply conditional formatting based on the value of the right column.

It does not matter if cells contain the date. The date is only necessary for a condition evaluation. The code that will conditionally format the background can easily operate on range of cells.

Answer 2

The new Google Sheets can do some of this. Follow the instructions here: https://support.google.com/drive/answer/78413?hl=en

Although it does not solve completely the question, you will be able to define one columns color based on a cell's value.

Hope it helped.

Ps: While I was testing it I have encountered some bugs in this feature so it may very well happen that it won't be really useful. We'll see...