Magnetic variation changes with a change in what?

Magnetic variation, also known as magnetic declination, refers to the angle difference between magnetic north (the direction your compass points) and true north (the direction along the Earth's surface towards the geographic North Pole). This variation is largely influenced by the Earth's magnetic field, which is not uniform across its surface.

As you change your geographic position on the Earth—moving north, south, east, or west—you can encounter variations in the Earth's magnetic field. This is due to the fact that the magnetic field can be affected by geological formations and other magnetic influences. Therefore, the magnetic variation that you might observe at one location will differ from that at another due to the underlying complexity of the Earth's magnetic field.

It is essential for navigators to be aware of magnetic variation, particularly as they travel across different areas, to make accurate adjustments for navigation. Understanding this concept is crucial for safe and effective seamanship.