Originally Posted by Fat Bribery
Mamoswine would be a great fit. In fact, one of the most common teams I've seen is Politoed/Starmie/Thundurus-T/Tornadus-T/Mamoswine/Filler (usually Ferrothorn or Jirachi). Mamoswine is great against opposing weather starters so it's a good Pokemon to have for winning the weather war. Plus, the Electric immunity it provides is more than welcome.
I think it wont be that great against most weather starters...
252 Atk Tyranitar (+Atk) Superpower vs 4 HP/0 Def Mamoswine: 97,79% - 115,47%
87,5% chance to OHKO
Mamo wont like being hit by that... and mostly being OHKO'ed.
He also wont enjoy being hit by a rain boosted scald (if burnded mamo become useless), surf or hydropump.
252 SpAtk Politoed (+SpAtk) Scald vs 4 HP/0 SpDef Mamoswine: 139,23% - 164,09% (in the rain)
0 SpAtk Politoed Scald vs 4 HP/0 SpDef Mamoswine: 98,62% - 116,85%
93,75% chance to OHKO (in the rain)
It also wont like to be burned by Ninetales WoW (if it carries, which most do), Solarbeam, also a move most Ninetales carrie will OHKO Mamo... Fire Blast do OHKO as well even with Thick Fat!
252 SpAtk Life Orb Ninetales SolarBeam vs 4 HP/0 SpDef Mamoswine: 103,31% - 122,1%
252 SpAtk Life Orb Ninetales Fire Blast vs 4 HP/0 SpDef Thick Fat Mamoswine: 116,85% - 137,57% (in the sun)
So as I still said, I think it wont be a good weather check unless it carries Fokus Sash or Scarf.