problem with getting information from column containg dates

I am struggling through this problem since yesterday, I have huge data set having 40 columns and 100 rows. 39 columns have data for specific date and 1st column contains that date. i need to plot graph of each data column separetely vs the date column taking only maximum value of data column for each month. date colum has multiple dates of same month but I need only that date in column for every month which has the maximum value
i am using excel 2010
Could anyone please help???

Uh...

Maybe create a pivot table of the data, put the date as the row value, and set MAX value for a given column as the column filter, then create a chart,
then clone the chart, change the column index,
and iterate till you have all your charts?

Anyway I feel like pivot charting will be the best approach.

With an example file, I'd be more comfortable saying more specific things.