Answered magnetic fields

[manawar]

                will the magnetic field be listed in the side quest when we get to one or will we just have to keep guessing? Some say it is the number of battles and others say it when you get to a mountain in the side quest. I for one would like a clear answer to this. it would be nice if a list was posted so ever one could see it. 

[Auke1993]

It's not specifically listed on Vortex where the magnetic fields are.

The magnetic fields correspond to the magnetic fields in the main games.
I will list these locations below.
In Sidequests, you go through all main game areas. This includes the areas with a magnetic field.

The 'numbers' you're referring to are the completed Sidequest battles. These are listed in Vortex as well.

After a certain amount of battles you'll enter Mt. Coronet in Sinnoh (I don't know exactly which battle is which area). This number is always the same. You'll be there for a few battles, and then exit and be in a new area.
While you are in Mt. Coronet in Sidequest, you can evolve Pokémon that need a magnetic evolution.

 

The same goes for all locations listed below. For example, if you replace Mt. Coronetin what I just wrote with Kalos Route 13, then you will have the special magnetic field as well.

All Magnetic Fields:
Hoenn - New Mauville
Sinnoh - Mt. Coronet

Unova - Chargestone Cave
Kalos - Route 13
Alola - Blush Mountain and Vast Poni Canyon.

The specific amount of battles you need to complete to get to each area I don't know.
All I have for you is the list of battles at which each Region starts and ends. Somewhere in there are the areas you're looking for. That way you'll at least have an approximation.

I hope this helped you enough.