Is Bigby's Hand affected by gravity, or does it hover in the air?

Question

The spell Bigby's Hand creates a translucent force that can be moved 60 feet in any direction:

You create a large hand of shimmering, translucent force in an unoccupied space that you can see within range. The hand lasts for the spell’s duration, and it moves at your command, mimicking the movements of your own hand.

[...]

When you cast the spell and as a bonus action on your subsequent turns, you can move the hand up to 60 feet [...]

Jeremy Crawford clarified that the hand can be moved in any direction, including up, in the air:

As the spellcaster, you can magically move the hand in any direction.

Once moved up, does Bigby's Hand fall? Or does it stay up in the air?

Other effects explicitly mentions if the entity is floating or hovering:

Arcane Eye: You create an invisible, magical eye within range that hovers in the air [...]

Guardian of Faith: A large spectral guardian appears and hovers

Mage Hand: A spectral, floating hand appears [...]

Mordenkainen’s Sword: You create a sword-shaped plane of force that hovers within range.

Spiritual Weapon: You create a floating, spectral weapon [...]

Tenser's Floating Disk: This spell creates a circular, horizontal plane of force, 3 feet in diameter and 1 inch thick, that floats [...]

Wall of Force: An invisible wall of force springs into existence [...]. It can be free floating [...]

Bigby's Hand is described as a "translucent force" but there is no mention of hovering, and I'm unsure if the hand would be affected by gravity.

Answer 1

There is no reason to assume the Hand is affected by gravity, although as long as the description of the spell is fulfilled, the GM could choose otherwise.

As you noted, the spell says:

When you cast the spell and as a bonus action on your subsequent turns, you can move the hand up to 60 feet

That is the only description of its movement. It has no speed, so it doesn't walk, climb, swim, or fly. The only way it moves is by the description above.

Also, the Hand is made of force. Other spell effects created by force do not appear to be subject to gravity; for instance, wall of force.

It is certainly easy to imagine the Hand as floating in air, but it could be interpreted differently. If the Hand is affected by gravity, then some way the narrative will need to account for the Hand's ability to be moved within its space. Perhaps it can stretch from the ground. It must be able to move freely within its range, either by floating, stretching, or some other method; otherwise in many cases it would be difficult for the Hand to fulfill at least the interposing hand form. The description of interposing hand makes no special explanation for a circumstance where the creature being interposed is in the air. To me, the narrative is intended to describe that the hand interposes itself regardless of location of the caster or the creature being opposed, as long as the hand can remain in range. So somehow it must be able to stretch, or float, or otherwise move to interpose itself.

Finally, for what it's worth, previous versions of the Hand, for instance Interposing Hand from D&D 3.5, describe the hand as floating.

GM's Ruling

In the end, it is up to the GM to interpret the rules. To my reading, it's clear that the Hand floats and that is how I rule, and how every GM I have played with rules. But there is nothing that keeps a GM from ruling oppositely, as long as the spell is allowed to work as described.

Answer 2

The hand is not affected by gravity and it can be moved in any direction.

The very beginning of the spell's description says:

You create a Large hand of shimmering, translucent force in an unoccupied space that you can see within range.

Since the range is 120 ft, one can create the hand 120 up in the air, and nowhere in the description is specified that if one does so it falls down on the ground, neither it includes anything that suggests that the hand may fall down if the caster moves it up to 60 feet in the air. As observed in Jack's answer, if it was affected by gravity the Interposing Hand would not work against flying creatures, for example.

If a spell effect is subject to gravity's effects, usually the description specify that. For example, the description of Tenser's Floating Disk includes (emphasis mine):

This spell creates a circular, horizontal plane of force, 3 feet in diameter and 1 inch thick, that floats 3 feet above the ground [...]

The Stinking Cloud lingers in the air (emphasis mine):

The cloud spreads around corners, and its area is heavily obscured. The cloud lingers in the air for the duration.

The Watery Sphere has a height limit (emphasis mine):

The sphere can hover but no more than 10 feet off the ground.

The fog produced by Cloudkill occupy the lowest level of the ground (emphasis mine):

The vapors, being heavier than air, sink to the lowest level of the land, even pouring down openings.

As observed in the question, there are several spells that create objects or magical effects that are specified to be hoovering: it is not the case of Bigby's Hand, but the description of the spell strongly suggests that the floating is implied. Otherwise, at the end of the caster's turn the hand would be laying in the ground due to gravity effects, or it would be standing up using one (or more) of its fingers.

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Pay attention that even some summoning spells includes the text

It manifests in an unoccupied space that you can see within range.

See for example Summon Undead. For being coherent with rules, a DM should rule that if a caster summons a creature in the middle of the air and such creature has not a flying speed they would fall to the ground. Bigby's hand is an object, per description, and has special rules of movement: the description suggests that it can hoover.

Answer 3

Guiding Principle: everyday expectations

Our guiding principle here, the RAI, comes from a 2020 tweet by Jeremy Crawford:

In D&D, everyday things—walls, gravity, bread, laughter—work the way we expect them to, except for when the rules say otherwise.
For example, D&D has magical effects that pass through walls, for walls are assumed to be impenetrable, unless you damage the wall itself.

Specifically referencing gravity, Crawford here says that we can expect it to work the way it does in our world, except when the rules say that it doesn't. In other words, sometimes the rules of D&D do not follow the rules of physics, but we will be specifically warned when they do not.

Turning to the Hand, we can find two references to how it moves in its description (emphases mine):

The hand lasts for the spell’s duration, and it moves at your command, mimicking the movements of your own hand.

Here we have the 'except when the rules say otherwise' part - the Hand can be moved by you up to 60 feet - this will not be affected by gravity (that is, you can move it sixty feet regardless of whether you are moving it up or down, it will not move faster if you move it down, unlike a normal object) and the Hand mimics the movements of your own hand. Your own hand, being an 'everyday' thing, is affected by gravity, and the Hand will mimic its movements. When you relax your hand, your fingers droop down, in the direction they are pulled by gravity, but only as far as their connection to your hand itself permits. Since the Hand is mimicking the movements of your hand, it will respond to gravity in a similar way - not because it is itself affected by gravity, but because your hand, which it is copying, is.

For the 'way we expect them to' part, should the Hand, as an object, fall when you are not moving it, since we expect objects to fall? Personally, I read the "moves at your command" as "moves [only] at your command", where the "rules say otherwise" is here specifying that gravity will not, in fact, cause the Hand to fall. However, I recognize that this is my interpretation, and is not explicitly RAW. For someone (perhaps the OP) seeking stronger evidence, let us assume that the hand will be affected by gravity - will it fall? What is our 'everyday expectation'?

As stated at the start, the spell specifically creates the Hand as an object, and ordinary objects fall. But the Hand is no ordinary object. Rather, it is an object made of "shimmering, translucent force" that "doesn’t fill its space". The fact that the Hand doesn't fill its space is important because it means that creatures cannot push against it. So, how would you expect an object made of force that doesn't fill its space and can't be pushed against to react to gravity? Would it fall? Would it drift? Would it re-orient?

I certainly don't have much everyday experience with such objects, and I expect most DM's don't. Thus, even for a reading of the spell that requires the Hand to be affected by gravity, it is completely unclear to me how it should be affected. This then becomes subject to DM ruling - the DM should decide how the Hand behaves in a manner that it consistent with other 'objects made of force' that exist in their world.