Getting ready

As done in the previous recipe, we will use the Oxford weather station's data. See the details in the Creating a time series plot recipe. Most of the steps in this example will be similar to the time series plot instructions, except the use of the multiple time series plots instead of a single one.

How to do it…

Let's get started with the steps that would help us add a secondary axis to a time series plot:

How it works…

Multiple charts that are overlaid are displayed on the same graph. When the scales are very different, as in this case where temperatures are in degree Celcius and sunlight hours in hours of sunlight in a month, then one response can appear disproportionate to the other. The secondary axis allows independent scaling of both axes while using the same x axis.

This can be a useful tool to display correlations in the data.