Magnetic fields are
weakest at the poles
strongest in the middle of the magnet
strongest at the poles

Magnetic fields are the strongest at the poles

Explanation:

The strength of the field varies depending on its location around the magnet.

Magnetic fields are the strongest in either both pole of the magnet. The magnetic fields are equally strong in north and south pole.

This because, near the poles, magnetic field lines are very close to each other. In other words , near the poles the magnetic flux density is maximum so the magnetic field is stronger at that position.

Those flux lines are the mathematical representation of the magnetic field and are continuous - a given line must always form a closed loop, that want to return to the opposite pole via air. Density of those lines is the so called magnetic flux density - the number of lines per unit square - determines how strong the field is in a given area of space.  As they spread out, their density drops, so does the magnetic strength. In actual open-circuited bar magnet you would see the strongest field on the edges of the pole, this is where the flux lines bend and concentrate.

Halfway between the poles, in the middle of the magnet, the magnetic fields are the weakest.