Conditional formatting Min and Max value within each month in a Clustered Column Chart

JackieC  It may just be because I love DAX so much, but I can't think of a solution without DAX for this one;

I would recommend unpivoting all the columns you're currently using in the 'y-axis' (both the column and line) - you can do this in Transform Data (Power Query).

Then create a measure for [Forecast] and put it in the column y-axis and a measure for [Actual Usage] and put it in the line y-axis

Then you can put the newly created 'Attribute' column (it will be created when you do the unpivot) in the x-axis and apply conditional formatting on the y-axis column colour.

DAX for measures:

Forecast = 
SUMX(
FILTER( tablename, CONTAINSSTRING( tablename[Attribute], "forecast") ),
tablename[value]

)

Actual Usage = 
SUMX(
FILTER( tablename, CONTAINSSTRING( tablename[Attribute], "actual") ),
tablename[value]

)