You cause numbing frost to form on one creature that you can see within range. The target must make a Constitution saving throw. On a failed save, the target takes 1d6 cold damage, and it has disadvantage on the next weapon attack roll it makes before the end of its next turn.

The spell’s damage increases by 1d6 when you reach 5th level (2d6), 11th level (3d6), and 17th level (4d6).

My Comments: First, I should mention that this was in the Elemental Evil Players Companion and Princes of the Apocalypse.
I like spells with secondary effects, it gives them more flavor and more role-playing potential. This one is okay. On their next weapon attack, they have disadvantage. The thing to notice about this, and separates it from Vicious Mockery, is that it only applies to weapon attacks. It doesn’t say ‘next attack’ or even ‘next melee attack’ but rather just ‘weapon attack’. It seems to me that it means it doesn’t apply to a monk’s or other’s unarmed strikes, though it does apply to both melee and ranged weapon attacks.

As a ranged damage spell, the range is shorter than cantrips like Eldritch Blast and Fire Bolt, and it does less damage. Wah-wah-wah-wahhhhhh. (sad trombone) It’s good that you don’t have to roll to hit, but the Constitution save negates the damage and I’m betting the opponent most likely to be using weapon attacks against you will have a pretty okay CON score. All told, it’s nowhere near as scary as real-world frostbite; 6 seconds after the effect you’re hurt but mostly good as new. Real frostbite? We’re talking amputated fingers and toes…

So what’s the upside? There doesn’t have to be an upside, sometimes a spells just isn’t that great. (See Friends)

Okay, there is are two upsides. You like the cold caster flavor and you want all of them. Cool, literally. Be that cold-blooded dragon sorcerer with a heart of gold, or whatever. Probably a warlock could boost this spell, or… something.

And, more importantly, the target has disadvantage on its next weapon attack roll. That’s a pretty good upside. If you stand back and Frostbite the heck out of the meatshield’s opponent there will be a lot less damage to the meatshield. Assuming the opponent doesn’t make their Con save, which they might if they’re also a front line fighter. Still though, causing disadvantage can be great!

Actually, I think it’s mostly a nice direct damage addition for Druids. I’d probably just use my action to shoot a bow though.

Am I missing something? Let me know!