So I really like the spell Zephyr Strike. I think a lot of people forget about it because it is locked down to just the ranger. 2 things I have wondered. 1. Why doesn’t the damage scale? And 2. Why isn’t it available to classes like the Hexblade Warlock, the Arcane Trickster Rogue, the Order of the Profane Soul Blood Hunter, or the College of Swords Bard? I understand the flavor and balance reasons, I just wish more classes had access to such a cool spell. 

1. Because they went out of their way to make the ranger as mechanically weak as possible (probably not but sure seems that way).
2. ATs just use wizard spell list and ZS is not a wizard spell. PS just use warlock list and ZS is not a warlock spell. Bard subclasses don't get bonus spells, but all bards get magical secrets. For hexblade, I guess they just figured Wrathful smite fit better.

If you talk to your DM, they might let you take it, I’ve had players convince me of why they should have spells that aren’t on their lists.

One thing I've never had satisfactorily explained is whether the speed bonus takes effect before or after the attack? My group says you only get it after attacking, so say if you were 60 feet an enemy and wanted to use ZS to close the distance, you couldn't. My understanding was the attack is the last part of the spell and the magic wears off afterwards, so the speed boost would have to come before the attack, as long as you still make an attack on that turn. 

Thoughts? 

The speed boost is very clearly written as happening after the attack. It specifically says whether you hit or miss you get 30 ft for the rest of the turn - heavily implies you must have taken the attack in order to get that speed boost.

My reading of:

"Once before the spell ends, you can give yourself advantage on one weapon attack roll on your turn. That attack deals an extra 1d8 force damage on a hit. Whether you hit or miss, your walking speed increases by 30 feet until the end of that turn"

was that the condition that signifies when the speed boost is not making the attack (the spell description does not mention making attacks to trigger anything), but rather the giving yourself advantage. Giving yourself advantage on an attack roll *that turn* doesn't have to happen simultaneously with the attack, the wording seems to present it as a separate condition. That would allow for something like: 

Cast ZS--->use for up to a minute---> on the turn you choose to end it on state "I'm giving myself advantage on one attack"---->take extra movement for rest of turn--->make attack with advantage---> spell ends

No from what I understand it's 1) Cast Zephyr Strike 2) In a turn during that minute - choose to make an attack with advantage 3) get 30ft extra movement for that turn because you made the attack.

Because the speed information is written after the advantage gaining and is specifically keyed to whether you hit or miss - it must come after the attack.

You can’t give yourself advantage on an attack until you know what attack you’re giving yourself advantage on, which doesn’t happen until you actually make the attack you’re giving yourself advantage on.

If the wording were “you have advantage on the next attack you make,” then there could be time between gaining advantage and making the attack. But with Zephyr Strike, you have to have a very concrete attack to say “I’m giving myself advantage on THIS attack.” Saying “I’m going to make an attack in two seconds after I’ve moved” doesn’t satisfy the condition, because there’s any number of potential circumstances that could arise and prevent you from making the attack at all.

I don't know, the text doesn't specifically say "whether you hit or miss, after you make your attack you gain 30 ft of movement"

Even the wording of the text is weird in the beginning

"You move like the wind. Until the spell ends, your movement doesn’t provoke opportunity attacks.

Once before the spell ends, you can give yourself advantage on one weapon attack roll on your turn. That attack deals an extra 1d8 force damage on a hit. Whether you hit or miss, your walking speed increases by 30 feet until the end of that turn."

Essentially what this is stating is you can Cast ZS, not use its effect and move for 10 rounds without proccing OA's, then on the 10th turn you gain advantage and 30ft of walking speed until the end of the turn.

There is no restriction stating that you MUST make the attack, it is simply stating, if you hit the attack or not, the movement is applied regardless. 

Flavor wise, i would play it as you muster up the power of the wind into an attack you have prepared, this grants you the extra movement.

The restriction that you must make an attack is inherent to the benefit: you cannot give yourself advantage on an attack if you don’t make an attack.

Ok ok, yeah I got that interpretation, I was just over here thinking "what's really the benefit of the 30 ft of movement after the spell ends when you're back to proving AoO's?" when I realized that triggering the attack bonus doesn't actually end the spell. 

Yea the spell lasts for a minute or until you lose concentration. Using the one time advantage doesn't change that. If it did - it would say so.

Question: Does the Zephyr Strike deal critical damage or is it just a 1d8 regardless?

Quote from BlueWolfX8 >>

Question: Does the Zephyr Strike deal critical damage or is it just a 1d8 regardless?

The extra 1d8 is part of the attack's damage, so it is doubled on a crit as well.

I wasn’t familiar with this spell but it does seem pretty nice that you can move around the battlefield for 1 minute and completely avoid  OA’s. Would be good for maneuvering around lackeys to get to a mage or something. 

The 30 feet is not "extra movement," it's an increase to your walking speed. If you have a way to move on your bonus action (cunning action, step of the wind), that would also benefit from the extra speed.

The spell does not end after the attack.

Rangers are not weak, they already a powerful DPR character.  If anything, they made Zephyr weak so as not to overpower the Ranger.  Also, it does a LOT, so it is hard to decide how to upslot it - more damage?  more speed?  Longer duration for the Advantage? Too complicated to upscale for a character that is NOT focused on spells. 

one of my players is playing a pirate themed hexblade so I gave him the ability to cast it once per day with his blade using a spell slot. it was thematically appropriate for the character but I see why it wouldn't work for a lot of others.

does anyone know if it would work on an unarmed attack? I am making a snowstorm themed monk sub and I want to give them the option to cast this spell with ki.

Quote from Schleme >>

does anyone know if it would work on an unarmed attack? I am making a snowstorm themed monk sub and I want to give them the option to cast this spell with ki.

Zephyr Strike requires a "weapon attack roll," and unarmed strikes are weapon attacks, so yes, they would work together.