Well, that SORT of worked but still does NOT do as I want.

Firstly, I have discovered that to use your suggestion, I needed to make the formula read: =if(INT(LEFT$b18,6))=42185,1,0) Note the addition of the INT

However, my date cells in column B are calculated.

Cell B18 has the starting date entered as 4/1/71 and formatted to read 4 January 1971.

Cells B2 down to 30 June 2021 are calculated from $b18 (relative) with the formula =$b18+1 and I do NOT want to change these to absolute values.

So, the conditional formatting formula above does NOT return the value 42185 for every 30 June.

Basically I want every row that is related to a 30 Jun date, no matter what year, to be underlined in red so I don't have to manually find all those rows and manually select the cells in that row to format and then format underline them! That is a REAL pain in the backside!

So, is this task at all possible?

Thanks for the feedback so far.