Select the cells you need to shade and use conditional formatting. Assuming
for this example that your dates are in column A and begin at A1, choose the
Formula Is option in conditional formatting and enter a formula like this:
=MOD(MONTH($A1),2)=1
and set the format. This will set shading for cells when it is an odd
numbered month, as Jan, Mar, May...November. If you use
=MOD(MONTH($A1),2)=0
the the even numbered months would be shaded.

"Sarah (OGI)" wrote:

I have a list of dates, in ascending order.
I'd like to be able to alternate the cell colour according to month, i.e.
all Jan dates need to be blue, all Feb dates need to remain white, all March
dates need to be blue, all April dates need to remain white, and so on.
I'm thinking this is some sort of conditional formatting?
Any ideas?