If the Conjure Elemental spell or Conjure Minor Elementals spell is cast in an area affected by a Hallow spell, does the summoning just fail?

Question

Hallow states "Celestials, elementals, fey, fiends, and undead can't enter the area..." but it doesn't say what would happen if someone tried to summon some into the area. Would the spell fail? Would the elementals appear but then be forced to leave?

Would the ruling be the same for both Conjure Minor Elementals and Conjure Elemental? The latter uses a source of the element (e.g. a fire, what if the fire is in the Hallow area?) while the former just makes some minor elementals appear from an unspecified source.

Answer 1

When something is summoned into a space it is still moving into that space

Something being summoned is simply teleporting something at somewhat random into a designated space. As such, since the spell is attempting to move them into the space, and they can't be moved there, logically, the spell would likely have no effect. They just, simply put, can't move into the space, so they just don't. If you can't move into a wall, you can't move into a wall.

Answer 2

The elementals can't enter.

It cannot come or go into a particular place by whatever means that don't override the spells restriction.

So what happens is that:

You summon elementals that appear in unoccupied spaces that you can see within range.

Whereas that space is outside of the 60ft radius of Hallow. The source of the spell component, in this case, has no impact on the restrictions (it does not change the nature of the elemental being an elemental which is what moderates the inability to enter).

Answer 3

Conjure Elemental does not work in hallow's area

tl;dr The vernacular meaning of "appear" and "enter" are synonymous in the sense used in the spells, and hallow prevents entry.

Appearing in a space is entering the space

The rules don't provide a definition of "enter" and "appear" so we use the common meaning of the terms.

Enter:

• to come or go into something

• to put in : insert

• to come into a preestablished situation or context like an actor coming onstage

The thing to note here is that the definition for enter doesn't remark about the mode of something going into or being put somewhere.

Appear:

• to come into existence

Appear is synonymous with enter in this case

Existence is something, coming into something by appearing is a form of entry. Entering into existence as per conjur elemental or conjur minor elemental within the area of hallow is entering (into existence) in hallow's area, which is explicitly disallowed by the spell.