Excel – Plotting Data with Discontinuous X-Axis Data in Excel 2013

There are at least two ways to accomplish this, one is pretty easy, the other is more difficult.

The Easy Way: As Simkill suggested, just create two (or more charts) and align them, creating an ad-hoc panel chart. By creating your base chart and choosing the formating, you can copy/paste that for subsequent panels ensuring that there's a consistent appearance. It would look something like this:

While this method is easier to set-up, it does require ensuring that your subsequent scales for both Axis are adjusted to ensure that your ranges are consistent. In particular, I'd set both Axis Min and Max values, rather then letting Excel do it automatically.

The Hard Way: You can also trick Excel into making you a panel chart with some specific data layout work. Basically, create an "arbitrary" X Axis with however many points you need for each data set, plus some additional blank values between your panels' values. You'll get something like this:

Once you're setup with this method, you don't have the same issues with scaling as above. In addition, you can use a second data series, format it as a column chart, and use that as banding (like the gray bands for each data series), to help better define breaks in the data sets.

Excel stores dates internally as whole numbers, times as decimals. The numbers you see are not random, but are the internally stored values for dates.

In a chart that supports a time/date x axis you will be able to set the minimum and maximum bounds by selecting a date, and you can set the major units to months. That is an option in line charts and column charts, for example.

XY Scatter charts don't have an option for a date axis and the minimum and maximum setting for the axis always show the underlying number of a date instead of the formatted date. That is independent of the number formatting you use to show the X axis labels.

Once you have worked out what date you want as the minimum date, enter it into a cell on a spreadsheet, then change the cell format to General. Now you can see which number you need to enter in the Minimum box. Rinse and repeat for the Maximum.

Unfortunately, the minimum and maximum cannot be linked to a cell (but you can add your vote here to have that feature added to Excel).

Also, in the Scatter chart there is no setting to increment major or minor units by one month. If you want the X axis labels to show the first of the month, you'll need to add a helper series with the dates on the X axis and zeroes as the Y values. Then hide the axis labels and add data labels for the helper series. Finally, hide the line and markers for the helper series.