This will be my last Rain Dance analysis for the moment. Zapdos is a great Pokemon for Rain Dance teams, and so onto the analysis. For the moment there is a block of text with some calculations so I am wondering whether I should change that into a little section with calculations, some thoughts on this would be nice.
STATUS: Finished!
Credits to Fuzznip for a lot of proofreading of all these Rain Dance analyses.
http://www.smogon.com/dp/pokemon/zapdos
[SET]
name: Rain Dance Support
move 1: Rain Dance
move 2: Thunder
move 3: U-turn
move 4: Roost / Protect
item: Damp Rock
nature: Modest
evs: 224 HP / 108 SpA / 176 Spe
[SET COMMENTS]
<p>Zapdos is a great Pokemon for Rain Dance teams because its insanely powerful STAB Thunder can tear through the bulky Water-types that cause most Swift Swim sweepers problems, specifically Vaporeon. Its immunity to Ground-type moves as well as its resistance to Grass-, Flying-, Bug-, and Fighting-type moves make it able to find an easy switch in when one of your Swift Swim sweepers are threatened. While Rotom-W may have both Thunder and Hydro Pump to take advantage of the rain, as well as better typing, Zapdos has higher Special Attack, instant recovery, and access to U-turn to separate it from Rotom-W.</p>
<p>U-turn is a great move for this set as it can scout for Pokemon like Celebi which may try to switch in on Thunder only to be brought into the range of one of your Swift Swim sweepers. If Zapdos is slower than the opponent's Pokemon, it means that it can get in your Swift Swim sweepers into play without taking the opposing Pokemon's attack. Roost gives Zapdos instant recovery and gives it much more survivability. However, if you are using Zapdos as your lead, Protect is a great alternative to scout for Explosion leads like Metagross and Azelf, as well as scouting Choiced users like Choice Scarf Jirachi. Other options for these two slots include Hidden Power and Roar. Hidden Power Ice provides the common BoltBeam combo with great coverage, while OHKOing Gliscor who may try to switch in on Thunder. However, Hidden Power Grass will OHKO Swampert, another Pokemon that may think its safe to switch in against Zapdos as Hidden Power Grass is uncommonly used by it. Roar is a lesser option, but can be used to phaze troublesome Pokemon like Baton Pass Ninjask.</p>
<p>Damp Rock is the preferred item to give your Swift Swim sweepers three added turns of rain that can be crucial for victory. However, Leftovers can pair well with Protect for free recovery, although Roost offers more than enough recovery anyway. Life Orb could be used to make Zapdos more of a sweeper under the rain, taking advantage of 100% accurate Thunder attacks. Generally, the extra turns of rain are more beneficial. A Modest nature is used to make Thunder as powerful as possible.</p>
<p>The EV spread is aimed at boosting the power of Thunder, outspeeding Adamant Lucario, LO Heatran and Smeargle, while also letting Zapdos take hits well. With 224 HP EVs you only have a 7% chance to be OHKOed by a +2 ExtremeSpeed + Stealth Rock damage from Adamant Lucario, this means you can beat one of Rain Dance teams most dangerous threats. As for the offensive side, 108 SpA EVs mean that Zapdos can OHKO the standard 188 HP / 0 SpD Bold Vaporeon 100% of the time, a 66.67% chance to OHKO the standard 252 HP / 0 SpD Bold Suicune, and even the bulkiest 252 HP / 252 SpD Calm Togekiss has a 28.21% chance to be OHKOed. 252 HP / 136SpD Calm Tentacruel takes a maximum of 84.62% from Thunder. All of these calculations assume that Zapdos is using Thunder and Stealth Rock is in play. These calculations mean that Zapdos can deal with many of the big threats to Rain Dance teams. An alternative spread of 156 HP / 176 SpA / 176 Spe can be used to deal more damage to the aforementioned threats, having a better shot at OHKOing them.</p>
<p>Without Hidden Power, Ground-types can laugh at this set because Thunder doesn't affect them. Luckily, Rain Dance sweepers like Kingdra and Ludicolo will have no trouble dealing with them. Salamence can come in after a kill to Draco Meteor Zapdos, therefore Steel-types such as Bronzong can easily switch in on Draco Meteor. Also, the rain allows Bronzong to nullify its Fire-type weakness, allowing it to better handle Fire Blasts coming from Salamence. Blissey walls this set easily, but physical Swift Swim sweepers like Kabutops and Qwilfish won't have much trouble with her. The great thing about Zapdos is most of the Pokemon that cause it trouble are already covered by the Swift Swim sweepers on Rain Dance teams, while Zapdos can deal with the Pokemon that cause Rain Dance sweepers trouble, making Zapdos a great support Pokemon on any Rain Dance team.</p>
STATUS: Finished!
Credits to Fuzznip for a lot of proofreading of all these Rain Dance analyses.

http://www.smogon.com/dp/pokemon/zapdos
[SET]
name: Rain Dance Support
move 1: Rain Dance
move 2: Thunder
move 3: U-turn
move 4: Roost / Protect
item: Damp Rock
nature: Modest
evs: 224 HP / 108 SpA / 176 Spe
[SET COMMENTS]
<p>Zapdos is a great Pokemon for Rain Dance teams because its insanely powerful STAB Thunder can tear through the bulky Water-types that cause most Swift Swim sweepers problems, specifically Vaporeon. Its immunity to Ground-type moves as well as its resistance to Grass-, Flying-, Bug-, and Fighting-type moves make it able to find an easy switch in when one of your Swift Swim sweepers are threatened. While Rotom-W may have both Thunder and Hydro Pump to take advantage of the rain, as well as better typing, Zapdos has higher Special Attack, instant recovery, and access to U-turn to separate it from Rotom-W.</p>
<p>U-turn is a great move for this set as it can scout for Pokemon like Celebi which may try to switch in on Thunder only to be brought into the range of one of your Swift Swim sweepers. If Zapdos is slower than the opponent's Pokemon, it means that it can get in your Swift Swim sweepers into play without taking the opposing Pokemon's attack. Roost gives Zapdos instant recovery and gives it much more survivability. However, if you are using Zapdos as your lead, Protect is a great alternative to scout for Explosion leads like Metagross and Azelf, as well as scouting Choiced users like Choice Scarf Jirachi. Other options for these two slots include Hidden Power and Roar. Hidden Power Ice provides the common BoltBeam combo with great coverage, while OHKOing Gliscor who may try to switch in on Thunder. However, Hidden Power Grass will OHKO Swampert, another Pokemon that may think its safe to switch in against Zapdos as Hidden Power Grass is uncommonly used by it. Roar is a lesser option, but can be used to phaze troublesome Pokemon like Baton Pass Ninjask.</p>
<p>Damp Rock is the preferred item to give your Swift Swim sweepers three added turns of rain that can be crucial for victory. However, Leftovers can pair well with Protect for free recovery, although Roost offers more than enough recovery anyway. Life Orb could be used to make Zapdos more of a sweeper under the rain, taking advantage of 100% accurate Thunder attacks. Generally, the extra turns of rain are more beneficial. A Modest nature is used to make Thunder as powerful as possible.</p>
<p>The EV spread is aimed at boosting the power of Thunder, outspeeding Adamant Lucario, LO Heatran and Smeargle, while also letting Zapdos take hits well. With 224 HP EVs you only have a 7% chance to be OHKOed by a +2 ExtremeSpeed + Stealth Rock damage from Adamant Lucario, this means you can beat one of Rain Dance teams most dangerous threats. As for the offensive side, 108 SpA EVs mean that Zapdos can OHKO the standard 188 HP / 0 SpD Bold Vaporeon 100% of the time, a 66.67% chance to OHKO the standard 252 HP / 0 SpD Bold Suicune, and even the bulkiest 252 HP / 252 SpD Calm Togekiss has a 28.21% chance to be OHKOed. 252 HP / 136SpD Calm Tentacruel takes a maximum of 84.62% from Thunder. All of these calculations assume that Zapdos is using Thunder and Stealth Rock is in play. These calculations mean that Zapdos can deal with many of the big threats to Rain Dance teams. An alternative spread of 156 HP / 176 SpA / 176 Spe can be used to deal more damage to the aforementioned threats, having a better shot at OHKOing them.</p>
<p>Without Hidden Power, Ground-types can laugh at this set because Thunder doesn't affect them. Luckily, Rain Dance sweepers like Kingdra and Ludicolo will have no trouble dealing with them. Salamence can come in after a kill to Draco Meteor Zapdos, therefore Steel-types such as Bronzong can easily switch in on Draco Meteor. Also, the rain allows Bronzong to nullify its Fire-type weakness, allowing it to better handle Fire Blasts coming from Salamence. Blissey walls this set easily, but physical Swift Swim sweepers like Kabutops and Qwilfish won't have much trouble with her. The great thing about Zapdos is most of the Pokemon that cause it trouble are already covered by the Swift Swim sweepers on Rain Dance teams, while Zapdos can deal with the Pokemon that cause Rain Dance sweepers trouble, making Zapdos a great support Pokemon on any Rain Dance team.</p>