This spell is worst overall compared to Ice Knife imo. It should have more damage or apply difficult terrain for a minute or something.

Yeah, and shatter deals more damage in a larger area for the same spell slot.

Quote from Cloudstorm >>

This spell is worst overall compared to Ice Knife imo. It should have more damage or apply difficult terrain for a minute or something.

 Ice Knife has a similar blast radius, but a successful save prevents all the frost damage, not just half. 

Quote from WillJewwel >>

Yeah, and shatter deals more damage in a larger area for the same spell slot.

 Shatter does a little more damage, thunder is a good damage type and the radius is wider. However, it risks friendly fire if not used carefully and it targets Con, which monsters tend to be decent at. Snowball Swarm can be cast from farther away (kind of a niche use), cold is still a decent damage type and it targets Dex.

Not all spells have to be "the best." Each has their uses and any wizard would want as many different ones in their spellbooks as they can get.

Actually this is better in some ways like that it's a save vs an attack roll. 

Shatter damages objects and this spell doesn’t. That could be seen as a benefit in some cases

I think this sentence is in the wrong order.

"A creature takes 3d6 cold damage on a failed save, or half as much damage on a successful one."

so many times this has happened where the Dm would tell us treasure like potions on your person or near the shatter are destroyed ....also seems a smart pick for an Ice based draconic sorcerer.

This is basically a fireball that deals cold damage and with less area of effect 

This spell should be 4d6 at least. By the DMG spell creation table it should do AT LEAST that, that table also assumes that the spell has some other effect, and probably assumes it has a better radius. Not damaging objects isn't enough of an effect to justify how bad the damage is, perhaps if it allowed you to choose creatures that don't get damaged it would be a bit better. I understand spells don't have to always be "The Best" but you shouldn't intentionally make spells that are far worse than any other option, it makes the people who want to make the thematic choice feel like they're weakening themselves for no reason.

Quote from tyranttoxicroak >>

... you shouldn't intentionally make spells that are far worse than any other option, it makes the people who want to make the thematic choice feel like they're weakening themselves for no reason.

 My Draconic (White) Sorcerer agrees.

this is a really "cool" spell

It’s a swarm of snowballs! Who cares if it’s underpowered?

I plan on having Krampus use it in my “Saving X-Mas” adventure because, well, because it’s a swarm of ficken snowballs!

I shot children with this in a x-mas one-shot 10/10

With much less damage and aow range

it is a snowball. remember the snowball fights you would have as a kid. In reality a SNOW ball doesn't really do any damage.  IMO this spell is overpowered for what it is. Ice should always do more damage than snow. just my opinion. 

Quote from Jamstah >>

This spell is worst overall compared to Ice Knife imo. It should have more damage or apply difficult terrain for a minute or something.

 If you are an Order of The Scribes wizard and find this on a spell scroll or spellbook, use this spell as "fodder" for One With the Word.  Do the same with other crappy spells, like find traps.  

Exactly I’ve used ice knife and I find when I use that spell I’m always damaging my team when I fail the roll needed to succeed. This spell at least if I fail would not explode on impact and hit team mate 

SSS has always done about half the damage of Fireball (although it used to be damage based on caster level not spell level). If you take the 8d6 at level 3 of Fireball, cut it in half, that's 4d6, it's the same as SSS cast at level 3. Where they failed here is the spell used to have a larger radius than fireball (30 vs 20) and it used to deal damage to objects, and creatures that had some affinity to fire would take double damage from it. The damage to objects kind of falls away because 5e is super specific that its damage is only cold where originally even though it was a cold-type spell the damage wasn't typed, and since it makes sense that a snowball hitting an object hard enough might damage it, it doesn't make sense that coldness itself would damage many different types of objects. There are a couple spells in 5e that deal bludgeoning and another type of damage and this should be one of them. Bringing it back to its original intent would leave the damage alone but increase the radius to 30 feet (so a 60 foot diameter sphere) and deal half of its damage as cold and half as bludgeoning. I think the part where it deals more damage to fire creatures isn't part of 5e's design language, rather they gave creatures vulnerabilities to certain damage types but only rarely.

You forget that sometimes a bigger blast is not what you seek. Humble yourself wizard