Plot two set of data with different time scales

Your original file in post #1 does not have any charts in it. I sometimes think it would help us help you if you included some of your failed attempts with an explanation of why they are unsuitable. It would also help us see what you have tried so we don't simply replicate a failed attempt.

That said, here's how I would probably do this:

1) Select one of the data series in the spreadsheet (A2:B821 maybe).
2) Insert -> line chart -> desired subtype -- you end up with a chart with one of the data series plotted.
2a) Make sure that Excel used a Date axis for the x axis and not a category/text axis.
3) Select the data for the other series (D2:D821)
4) Copy to clipboard -> Select chart -> Paste Special -> as new series with x values in 1st column but do not replace existing categories.
5) In the chart, select which data series you want on the secondary axis. Format -> selected data series -> move to secondary axis.
6) With the chart selected: chart group -> Layout -> Secondary horizontal axis -> show left to right axis.
7) Format secondary x axis so it has the same min/max/major/minor as the primary axis.

Help file for adding secondary axis system: https://support.office.com/en-us/art...8-4ffafe2a1080

I would try that, then see if that gives you what you want. If that does not give you what you want, explain where it goes wrong.