Can you cast a spell with a casting time of 1 action while falling?

Question

Can you cast a spell with a casting time of 1 action while falling assuming you are falling for at least one turn before hitting the ground.

I want to have some insight into the possibility of a PC casting a spell while falling. This could be any spell that requires 1 action to cast.

In combat 1 action is part of a "turn", so it will happen within 6 seconds tops. Though, realistically, in combat a turn could include other things; an action, bonus action, reaction, etc. For the sake of simplicity for this question assume that the PC is not in combat and is falling for more than 6 seconds.

This question is not specifically about the spell Feather Fall, as my question is about spells that require 1 action to cast, not a reaction. If you need to use Feather Fall to expand a point, please do, but bring this back to spells that take 1 action to cast.

I appreciate both RAW and RAI responses in this case. If you can provide references and a spell in your example, even better.

Thanks for your help with this.

Answer 1

Per the RAW spellcasting rules, yes. But there are intricacies to consider.

The following excerpts are taking from the PHB, Chapter 10, pages 202-205.

Regarding casting time:

Most spells require a single action to cast . . .

Here we see there are no restrictions on what is happening during a turn, other than the caster needing to spend the appropriate action.

Regarding range:

The target of a spell must be within the spell's range . . . once a spell is cast, its effects aren't limited by its range, unless the spell's description says otherwise.

Again, nothing prohibiting positioning, only that the target be in range at the moment the spell is cast.

Regarding components:

Verbal: Most spells require the changing of mystic words . . . a character who is gagged or in an area of silence . . . can't cast a spell with a verbal component.

Somatic: Spellcasting gestures might include a forceful gesticulation or an intricate set of gestures . . .

Material: . . . A spellcaster must have a hand free to access a spell's material components - or to hold a spellcasting focus - but it can be the same hand that he or she uses to perform somatic components.

Here, there is nothing RAW stating these cannot be done while falling. However, you as a DM are within your power and reason to determine if components are possible, or only possible with checks, to satisfy the spell's requirements.

For example, somatic components simulate gestures that may be difficult to perform while plummeting toward the ground. It may warrant a Dexterity or Athletics check to pull off against the wind and other forces affecting the caster. Likewise, it might be hard to keep hold of a large staff while spinning wildly in the air. Concentration can be used as a catch-all for the difficulty of the situation.

I haven't personally employed these (I tend to complicate my encounters enough IMO), but I have played at a table where our DM used such techniques sparingly. A particular instance was a vicious storm in which our PCs were described as struggling to even walk upright; the DM had the wizard make a Strength (Athletics) check to be able to hold his arm out with his staff to cast. I agreed with the rationale, and I felt it added a sense of weight and severity to the situation, as well as cause for celebration when the player succeeded. This was the general result we got from whenever the DM employed this technique, in that we felt it added realism and value overall to the story.

Again, none of these are required explicitly in RAW, but are reasonable considerations based on the scenario and what you want your players to accomplish.

Answer 2

The core rulebooks don't specify any rules for falling (only landing)

Here's what the PHB and Basic Rules have to say about falling:

A fall from a great height is one of the most common hazards facing an adventurer. At the end of a fall, a creature takes 1d6 bludgeoning damage for every 10 feet it fell, to a maximum of 20d6. The creature lands prone, unless it avoids taking damage from the fall.

That's it. There's no rules about how, when, or how fast you fall, just what happens at the end of the fall. As with all things in 5th edition, that means that the precise mechanics of falling are determined by the DM. Given that 6 seconds (the length of one round) is enough time to fall hundreds of feet in real life, in most situations and environments your fall would be over by the end of your turn, so you generally wouldn't have time for a mid-air action.

Xanathar's Guide to Everything provides an optional long-fall rule

However, for longer falls, XGtE gives an optional rule that a DM can use to cover long falls that last longer than 6 seconds:

When you fall from a great height, you instantly descend up to 500 feet. If you’re still falling on your next turn, you descend up to 500 feet at the end of that turn. This process continues until the fall ends, either because you hit the ground or the fall is otherwise halted.

There's nothing in this rule or any of the other optional falling rules presented in XGtE that limits what kind of actions you can take on your turn while falling. So, using this optional rule, there's nothing stopping you from casting spells while in freefall. However, the DM would likely be within their right to demand a Constitution saving throw to maintain concentration on any spell while falling this fast, as described in the rules for concentration:

The DM might also decide that certain environmental phenomena, such as a wave crashing over you while you're on a storm-tossed ship, require you to succeed on a DC 10 Constitution saving throw to maintain concentration on a spell.

Tumbling chaotically in midair or having the wind whipping past you at terminal velocity could certainly be at least as disruptive as a wave crashing over a ship.

Answer 3

There is no RAW answer

As far as I can tell, the only rules regarding falling is how much damage you take based on how far you fall (PHB page 183).

There is this answer from Christopher Perkins to how far you fall within 6 seconds (~580 ft), but obviously that doesn't answer your question. It could be argued that since it was worth answering how far you fall, that implies they would allow you to take an action during said fall (i.e. "You can take an action only if the fall is approximately 580 feet"), but that may be reaching a bit.

There's also this other answer from Jeremy Crawford where they are asking about casting dimension door while falling, and Jeremy simply says "There's no rule to govern such a situation," regarding the conservation of momentum. Again, this implies that you can, but still isn't a clear answer (but Jeremy did also basically say that he would allow it as a DM in his answer).

(As always, DISCLAIMER: these are not official rulings, but the opinions of the designers. Thank you to @mdrichey for correcting me)

There are also no rules disallowing it, though, so I would say it's up to the DM.