This being the new NU tier, http://pokemondb.net/pokebase/meta/7997/outline-nu-split
It's not entirely a hail based team, I only have 3 benefiting members, 2 of which set it up, but it works.
Spiffy (Vanilluxe) (M) @ Icy Rock
Trait: Ice Body
EVs: 4 HP / 252 Atk / 252 SAtk
Relaxed Nature (+Def, -Spd)
- Hail
- Blizzard
- Taunt
- Explosion
Jelly (Duosion) (M) @ Life Orb
Trait: Magic Guard
EVs: 48 HP / 144 Def / 252 SAtk / 64 SDef
Modest Nature (+SAtk, -Atk)
- Trick Room
- Psyshock
- Energy Ball
- Shadow Ball
Spiffy Jr. (Vanillish) (F) @ Eviolite
Trait: Ice Body
EVs: 12 HP / 244 Def / 252 SDef
Bold Nature (+Def, -Atk)
- Blizzard
- Attract
- Hail
- Hidden Power [Electric]
Effiel 65 (Sawk) (M) @ Choice Band
Trait: Mold Breaker
EVs: 4 HP / 252 Atk / 252 Spd
Jolly Nature (+Spd, -SAtk)
- Close Combat
- Earthquake
- Stone Edge
- Poison Jab
WeatherLover (Castform) (M) @ Choice Specs
Trait: Forecast
EVs: 4 HP / 252 SAtk / 252 Spd
Timid Nature (+Spd, -Atk)
- Weather Ball
- SolarBeam
- Thunder
- Shadow Ball
Pack Rat (Raticate) (M) @ Flame Orb
Trait: Guts
EVs: 4 HP / 252 Atk / 252 Spd
Jolly Nature (+Spd, -SAtk)
- Facade
- Wild Charge
- Zen Headbutt
- U-turn