Leomund's tiny hut can protect against magic, objects, and creatures from entering.
A dragon's breath weapon is not considered magical, but has to be an object at least - which should be blocked by the hut.
Sage Advice, however, rules that a dragon's breath can pass through the hut. I typically rule with Sage Advice, but is this a situation where Crawford got it wrong?
Can a dragon's breath weapon pass through Leomund's tiny hut?
I agree with other answers that RAW a dragon's breath can pass through the Hut.
However, I believe that in this case, sticking to a RAW ruling can hurt your game.
In any other situation, the Hut prevents just about anything, any attack from passing through. The dragon breath is an edge case that diverts from the simple rule and will damage immersion for your players (source : when I told my players about this ruling, the answers I got were "Wait what?", "That makes no sense" etc. and we collectively decided to ignore it)
The Hut aims to provide a safe space to rest, where the players can't be attacked from the outside. This ruling makes no sense in that context, and is (in my opinion) just the result of a poorly-worded spell.
Here is the relevant text from tiny hut
All other creatures and objects are barred from passing through it. Spells and other magical effects can’t extend through the dome or be cast through it.
Since
it can extend through the dome, and of course deals damage to anyone caught within its area.
This is supported by Jeremy Crawford's tweet.
The breath weapon of a dragon is not a spell or magical effect and presumably wouldn't be considered an object so would go through Leomund's Tiny Hut like it wasn't there, yes?
That's correct.
While the ruling is considered unofficial, since it is not on the Sage Advice Compendium yet, his ruling is considered significant since he is the rules designer of DnD 5e. His ruling usually is a good barometer on how the intent of published rules should work.
RAW, the dragon breath is not blocked by tiny hut, but the DM is always free to rule otherwise, possibly by ruling that a fire breath or cold breath is negated by this clause:
The atmosphere inside the space is comfortable and dry, regardless of the weather outside.
Leomund's Tiny Hut blocks three classes of things: Creatures, Spells/Magical Effects, and Objects. Let's treat these in turn:
Dragon Breath is not a creature. This is not in dispute.
Dragon Breath is not a Spell or Magical effect, on the basis of this Sage Advice which is a bit long and florally worded to reproduce, but draws a distinction between the pervasive, ambient magic of the D&D world vs the concentrated magic of a Spell or Magical Effect. Dragon Breath is placed definitively in the first category and beyond the reach of Anti-Magic Shield, and presumably also Leomund's Tiny Hut.
Dragon Breath is not an object. The DMG on page 246, as referenced by this answer and this Crawford tweet, defines an object as:
For the purpose of these rules, an object is a discrete, inanimate item like a window, door, sword, book, table, chair, or stone, not a building or a vehicle that is composed of many other objects.
And this answer draws on that definition to opine (and I agree) that gasses and liquids don't qualify as objects because they are not discrete items. On that basis, it is hard to see how any of the traditional Dragon Breaths listed in the 5e MM (acid, fire, poison gas, lightning, sleep gas, repulsion energy, slowing gas, weakening gas, paralyzing gas, icy cold) could be considered as discrete objects.
Since it fails all three tests, it is not blocked.
As I mentioned in the comments, JC's tweets on twitter are considered as advice, not official rulings. However, as per the Sage Advice Compendium:
Official rulings on how to interpret rules are made here in the Sage Advice Compendium by the game’s lead rules designer, Jeremy Crawford (@JeremyECrawford on Twitter).
So the process is that people ask JC for advice on Twitter. The development team then publish any of these posts that they consider to be fair and accurate interpretations of the rules into the Sage Advice Compendium.
One clarification they have made is that Dragon's breath in not magical, by the definition of what interacts with Leomund's Tiny Hut:
Is the breath weapon of a dragon magical?
If you cast antimagic field, don armor of invulnerability, or use another feature of the game that protects against magical or nonmagical effects, you might ask yourself, “Will this protect me against a dragon’s breath?” The breath weapon of a typical dragon isn’t considered magical, so antimagic field won’t help you but armor of invulnerability will.
So, following that ruling, JC's tweet is correct; Dragon's breath is not magical, by the definition of the requirements of the Leomund's Tiny Hut spell; the breath won't be blocked by the hut.
The key line of the spell that prevents it is emphasised in this quote:
Creatures and objects within the dome when you cast this spell can move through it freely. All other creatures and objects are barred from passing through it. Spells and other magical effects can't extend through the dome or be cast through it. The atmosphere inside the space is comfortable and dry, regardless of the weather outside.
It is important to point out that the modifier added to the end of the last sentence in that quote:
[...] regardless of the weather outside.
Means the last sentence applies to "weather" from outside the hut affecting the "atmosphere" inside the hut. Notably, it means the sentence does not cover things originating inside the hut from changing the "atmosphere" inside the hut. All effects should be viewed with this lens applied. For our purposes, the dragon's breath weapons definitively originate outside of the hut, and are thus caught by this sentence.
First things first, "weather" is defined as:
the state of the atmosphere with respect to heat or cold, wetness or dryness, calm or storm, clearness or cloudiness
or
disagreeable atmospheric conditions: such as
- RAIN, STORM
- cold air with dampness
Next "atmosphere" which is defined as:
the air of a locality
or
the gaseous envelope of a celestial body (such as a planet)
So, in particular the gases inside the hut will always be comfortable and dry. The types of dragons breath we have currently in the game can be summarised as follows:
The gas forms of breath are immediately excluded, as they would make the atmosphere in the hut decidedly uncomfortable (unless the caster is immune to the specific gas).
Acid is also excluded as, by definition, acid is:
a sour substance
specifically : any of various typically water-soluble and sour compounds that in solution are capable of reacting with a base (see BASE entry 1 sense 6a) to form a salt, redden litmus, and have a pH less than 7, that are hydrogen-containing molecules or ions able to give up a proton to a base, or that are substances able to accept an unshared pair of electrons from a base
This is excluded explicitly by virtue of the requirement to that the interior of the be dry regardless of what is happening outside. So the hut is clearly capable of blocking liquids, and getting doused by a liquid is the very definition of being wet:
consisting of, containing, covered with, or soaked with liquid (such as water)
The Icy Blast is also excluded, as it causes cold damage by drastically lowering the temperature. We can see this from the description of the White Dragon:
[...] Larger treasures and chests are encased in layers of rime created by the white dragon's breath, and held safe between layers of transparent ice.
I don't know about you, but temperatures cold enough to cause accumulations of a crust of ice on objects would be a decidedly uncomfortable environment to be in (unless you are immune to the cold). They are also firmly in the definition of "weather" presented above.
That leaves us with Fire and Lightning breath. We know the dragon's breath weapon is not magical (as confirmed by an official Sage Advice ruling), as a result the Fire and Lightning produced respectively is not magical Fire or Lightning. This means it needs to conform to the regular rules for such occurrences.
So we need to ask:
Fire is defined as:
fuel in a state of combustion (as on a hearth)
For fire to exist, three things are required, Oxygen, fuel and heat. We clearly have heat and Oxygen, so that leaves the fuel. Thus, in order to exist as fire in the hut the fuel the dragon's breath is burning must travel with it into the hut. The fuel itself is certainly an object (or at least each element of fuel is an object) and as a result cannot pass into the hut. All that remains is the heat. Again, I don't know about you, but being in a hut with air hot enough to cause significant damage is not my idea of a comfortable atmosphere! Additionally, "heat" falls under the definition of "weather" outside. Thus the fire breath is blocked by the hut.
Lightning is defined as:
the flashing of light produced by a discharge of atmospheric electricity
Here the definition contains the key word, atmosphere! An electrified atmosphere is not a comfortable one for most forms of life! Thus we must conclude that the hut also blocks lightning breath.
Side Notes:
RAW, the breath attack shouldn’t penetrate.
I’d cite the clause of the spell which explicitly describes it as “a wall of force”, which stands to reason that it provides an equal and opposite reaction force to a body exerting force onto it. The hut can clearly repel water from its weather control clause, so it stands to reason that an acid breath attack would be repelled.
As for lightning breath weapons, if the hut can repel a lightning strike in a thunderstorm, then the breath attack shouldn’t pass through either.
As for fire breath attacks... I can see two different ways that plays out. Either the breath attack is like a flamethrower, which spews out napalm, hence acting as a more viscous fluid, or it’s more like an acetylene gas torch, where the fluid combusts completely, and “flame” part of the fire is just extremely hot gas particles being propelled by the pressure with which the gas was expelled. If it’s more like the first case, then the fluid would be repelled as if it were rain. If it’s superheated gas particles, the hut should block (most) of the particles from passing the boundary as it would block liquids. I’m treating a gas as just a not-very viscous Fluid over here.
As for the heat.... it’s most likely a constant pressure-type combustion because once the breath attack is released, the gas expands when combusted, hence volume increases. The heat energy is transferred via the work done by the gas particles on whatever object is being bombarded by them. If the gas particles are indeed blocked, then most of the heat should be mitigated between the force wall and temperature control from the spell effect.
No idea how repulsion breath would interact. It’s not strictly magical, and I can’t think of any physical explanation for it.
I know this is pretty old, but I would like to add that as per the Monster Manual
Dragons are also magical creatures whose innate power fuels their dreaded breath weapons and other preternatural abilities. Pag. 86, MM
I would interpret it as this: dragons' "innate power" is granted by their status as magical creatures, the innate power fuels their breaths, thus their breaths are magical.
Thus, tiny hut protects against it.
I'll go with a dictionary definition...
What is an "object"? Well, according to Merriam Webster an object can be "something material that may be perceived by the senses" (according to definition 1.a).
So how do we define "something material"? It's something "relating to, derived from, or consisting of matter" (according to definition 1.a.1)...
So how do we really define "matter"? For this once, we have to read more than simply the first entry...
Looking up "matter" in a dictionary, I find entry number 2 relates to the relevant use of the word "matter", as is clearly demonstrated by 2.a: "the substance of which a physical object is composed".
Reading on entry 2.b tells me everything I need to know... "material substance that occupies space, has mass, and is composed predominantly of atoms consisting of protons, neutrons, and electrons, that constitutes the observable universe, and that is interconvertible with energy".
Great! So the gasses which fire consists of IS technically matter, furthermore we now know that a fire is "material" and it can certainly be perceived by the senses...
So fire is, technically, an object. Therefore a dragon's breath can't pass through a Leomund's Tiny Hut by RAW, just like it can't rain into the hut and just like I can't shovel sand on the hut and have it pass through.
(Oxygen CAN however pass into the hut, since we can't perceive it with the senses, only the lack of it can be perceived, and then only from the effect not having oxygen has on our bodies, we're not actually perceiving the oxygen. Conversely the same is true of certain harmful gasses...)
