Modest nature, Choice Scarf. I've tried out specs-toed, and it's not bad. Scarf is better though, so you'll want to run that. Fill out EVs. ( 4 HP ) Oh, and Drizzle would be a good idea here :P
DB tiers no longer exist, so SS in OU is banned.
If you're still just dying to run SS, ( or you're using PO tiers and they haven't banned that in OU. I think they have, but I'm not 100% sure ) then you can run one of the first two sets, standard frosty-bear. Works great.
Or, if you don't want to run SS.
Beartic (M) @ Life Orb
Trait: Snow Cloak
EVs: 252 HP / 252 Atk / 4 Spd
Adamant Nature (+Atk, -SAtk)
- Shadow Claw
- Ice Punch
Tank. Ghost + Fighting gives awasome coverage, Ice Punch is STAB, Dive gets a 50% boost, which is like STAB. ( Because it's raining. )
Run Timid over Modest for the out speeding factor. Life orb gives enough of a power boost. Fill out EVs ( 4 HP )
Way too many SA EVs. Put 100 of those into HP and only run 56 into Special Attack.
Replace Mirror Shot with Toxic Spikes, status is always a helper.
Raikou @ Leftovers
EVs: 4 HP / 252 SAtk / 252 Spd
Rash Nature (+SAtk, -SDef)
- Weather Ball
- Aura Sphere
- Shadow Ball
Shadow Ball > HP ghost any day. Thunder is STAB. Nature HAS to be Rash to have this moveset ( It has a move or two from the event Raikou, who was Rash ) Aura Sphere helps Shadow ball with coverage. Weather Ball gives the full rain power experience.
You need to run a physical set, due to the layout of the rest of your team.
Mew @ Expert Belt
EVs: 4 HP / 252 Atk / 252 Spd
Jolly Nature (+Spd, -SAtk)
- Hone Claws
- Aqua Tail
- Zen Headbutt
This set should work, you can also run Stone edge or Superpower in the last slot ( Earthquake's slot ) and you should be good.