New to this: How do I display the difference of two interpolated curves all on one graph?

Hi all
So sorry if this has been discussed before, didn’t manage to find an exact match in searches.
I am very new to this, and cant figure out how I display a line graph representing the difference (temperature, in degrees C) between two other temperature graphs.
I have:

  • A temp sensor in a shed
  • A temp sensor sourced from OpenWeatherMap

Both seem to be interpolated, ie different data points at different times.



Poease provide sample data of shed (meteic and value) and what is the datasource of shed temps?