What atmospheric phenomenon often exaggerates the perceived size of the Moon near the horizon during a supermoon?

Answer

The Moon Illusion

The Moon Illusion causes the Moon to look substantially bigger when it is near the horizon compared to when it is higher in the sky, even though its actual angular size has not changed due to orbital mechanics.

What atmospheric phenomenon often exaggerates the perceived size of the Moon near the horizon during a supermoon?
astronomysupermooneffect