Magnetic declination self-updating in map layout

[MaciekB]

Hi,

I am setting a map series using Data Driven Pages and the aim is to have the series as automated as possible. One of the elements that would ideally be automated is the value for the magnetic declination. Currently this information is manually calculated using an online calculator and then manually entered into the layout. This series will have 395 tiles so it is not practical to do a manual calculation for each one every time.

Is there a way of somehow making the declination angle a dynamic text element that updates itself based on the map tile and date?

Thanks