Raikou is quite the stereotypical Electric-type Pokemon: good Special Attack and Speed with a fairly bland movepool. Its excellent combination of base 115 Speed and Special Attack stats looks great on the surface, but unfortunately as an offensive Electric-type Pokemon it receives major competition from Thundurus-T and Jolteon in the OU environment, each having significant advantages that warrant more usage on OU teams. In addition, while Raikou does have some neat event moves in Aura Sphere and Weather Ball, it is forced to run a Rash nature when using either of them. This hurts its ability to fully take advantage of its excellent base 115 Speed (although it can still outspeed base 100 Speed Pokemon by a single point). Because of this, Raikou generally does not find much usage on OU teams.
However, Raikou does have some notable assets that give it an edge over its competition. Unlike its competitors, Raikou has good 90 / 100 special bulk to compliment its offenses and give it the ability to take a few hits when needed. The extra speed is also useful for checking prominent threats like Garchomp and Keldeo, which Thundurus-T is unable to do without a Choice Scarf, and the extra power gives it an advantage over Jolteon. Aura Sphere and Weather Ball are two great coverage moves that Thundurus-T and Jolteon would love to have. Raikou even has unique access to Calm Mind, allowing it to boost its special power and bulk simultaneously, which in turn makes it a more powerful and more durable sweeper. Utilize these niches and Raikou will never disappoint.
On a side note, you should always make your Raikou shiny since all event Raikou are supposed to be shiny. A non-shiny Raikou is a clear signal that you are not running Aura Sphere or Weather Ball.
This set aims to take advantage of one of the unique and effective tools at Raikou's disposal: Calm Mind. Raikou's excellent base 115 Special Attack and Speed make it hard to stop once it has a Calm Mind boost or two and its good special bulk is further enhanced. Thunderbolt is the STAB move with the best combination of reliability and power and Hidden Power Ice compliments Thunderbolt's coverage almost perfectly, forming a combination resisted only in OU by Thick Fat Mamoswine and Magnezone. There are a few viable options for the last slot. Although Aura Sphere forces Raikou to run a Rash nature, it threatens Kyurem-B, Terrakion, Heatran, Mamoswine, Tyranitar, and Ferrothorn, several Pokemon that would otherwise be very dangerous to the success of this set. Substitute can be used to ease prediction when forcing switches, protect Raikou from dreaded status moves, and even take weaker attacks with ease once Raikou has accumulated enough Calm Mind boosts. Defensive Latias's Dragon Pulse fails to break Raikou's Substitute the majority of time after Raikou has a Calm Mind under its belt, and defensive Celebi without Perish Song becomes helpless against Raikou with a Substitute and a Calm Mind boost. Volt Switch seems strange on a boosting set, but does have its use. With Volt Switch, Raikou can steal the momentum and wear down its checks early- and mid-game, which will help soften up the opponent's team for a late-game Calm Mind sweep. This gives Raikou much more utility in the earlier parts of the game, where it might find it difficult to sweep with Calm Mind. It is also worth noting that if you run either Substitute or Volt Switch, Raikou can freely run a Timid nature and take full advantage of its base 115 Speed.Team Options & Additional Comments >>>
With such a great combination of Special Attack and Speed, it is no surprise that Raikou would be able to run a successful Choice set. When wielding a Choice Scarf, Raikou becomes an excellent check to many offensive threats such as Salamence, Gyarados, and Dragonite with a Dragon Dance boost, as well as fast Pokemon such as Terrakion and Keldeo. Even when running a Rash nature, Raikou is still able to outspeed Pokemon with a base 100 Speed stat, which makes it an effective Choice Scarf user even without a positive Speed nature. Raikou can also forgo the revenge killing utility of the Choice Scarf in favor of the raw power of Choice Specs-boosted attacks. Thunderbolt is again the primary option for a STAB move. Hidden Power Ice makes a great coverage move alongside Thunderbolt, and it gives Raikou a weapon for revenge killing Pokemon such as Salamence, Dragonite, and Thundurus-T. Aura Sphere covers Pokemon such as Tyranitar, Kyurem-B, and Mamoswine, and it is a great move for revenge killing Terrakion without a Rock Polish boost or Choice Scarf. Signal Beam can be used instead if you need the extra coverage against Pokemon such as Celebi, Latios, and Latias. More importantly, you are free to run a Timid nature on Raikou when using Signal Beam instead of Aura Sphere. Volt Switch is an excellent option for the last moveslot. With Volt Switch, Raikou can deal significant damage to a wide variety of Pokemon while also stealing the momentum for its team.Team Options & Additional Comments >>>
By running an all-out attacker set, Raikou is able to take advantage of its great coverage and overall offensive presence without the restrictions of a Choice item. The combination of Thunderbolt and Hidden Power Ice is the primary choice for the coverage that it offers. However, because this particular set works very well on weather teams, Weather Ball makes for a particularly useful and powerful coverage move. Like Hidden Power Ice, Weather Ball in hail can form the excellent BoltBeam coverage alongside Thunderbolt, handling many of the Ground- and Grass-type Pokemon that could normally handle Electric attacks with ease. Weather Ball in sun or rain can also cover Grass- and Ground-type Pokemon, respectively, and Weather Ball will gain an additional power boost from the weather. If used on a rain team, Thunder can also be used instead of Thunderbolt for the extra power and higher paralysis rate. Aura Sphere is the best option for the third slot due to the coverage it offers against opposing Kyurem-B, Mamoswine, Ferrothorn, and Tyranitar. This set is a good user of Volt Switch. However, Signal Beam can be used to hit Latias and Celebi much harder, both of which might wall Raikou completely depending on which Weather Ball type it is using.Team Options & Additional Comments >>>
Despite some of Raikou's neat move options on the main sets, it has a fairly lacking movepool otherwise. Extrasensory can be used to hit some Fighting- and Poison-type Pokemon harder than Thunderbolt, notably Terrakion and Venusaur. Other Hidden Power types can be useful from time to time. For example, if you are not running Aura Sphere or Weather Ball on a sun team, Hidden Power Fire can hit Ferrothorn very hard. Shadow Ball hits Latios and Latias a little harder than Signal Beam or Hidden Power Ice while also hitting Celebi pretty hard. However, it does not cover much else that Signal Beam does not already handle. ExtremeSpeed is another move that Raikou obtained via event. Although it works off of Raikou's lower base 85 Attack stat, it can be used to 2HKO faster threats in tandem with one of Raikou's other moves. For example, Latios and Venusaur are 2HKOed by the combination of Hidden Power Ice and ExtremeSpeed, while Choice Scarf Kyurem-B is 2HKOed by the combination of Aura Sphere and ExtremeSpeed (each of these after Stealth Rock). It should be noted that ExtremeSpeed should only be considered on an all-out attacker set. Charge Beam can deal a small amount of damage with each hit and raise Raikou's Special Attack a majority of the time, but it is initially very weak and is honestly outclassed by Calm Mind. Raikou also has a pretty good support movepool, boasting options such as Reflect, Light Screen, Roar, and Thunder Wave. However, Raikou's niche lies in its offensive prowess, and so it would be best to leave the support to something else.
Checks and Counters
Blissey and Chansey are perhaps the most notable counters for Raikou, as is the case with many special attackers. Raikou has trouble getting past either of these Pokemon without significant amounts of Calm Mind boosts. Specially defensive Hippowdon can handle even a Choice Specs-boosted Hidden Power Ice and threaten back with Earthquake. It can also change the weather to sandstorm, alleviating the threat of Weather Ball. As Raikou can not run every coverage move at once, several other Pokemon are capable of handling it depending on which combination of moves it chooses. If Raikou is not running Hidden Power Grass, Gastrodon and Quagsire can easily handle almost anything that Raikou can dish out and threaten back with STAB Ground moves. Tyranitar is gravely threatened by Aura Sphere, but otherwise it switches in fairly easily and can heavily damage Raikou with Stone Edge or Crunch. Kyurem-B's bulk lets it easily handle anything besides Aura Sphere and severely damage or OHKO Raikou with its Dragon STAB. Ferrothorn fears nothing from Raikou bar Aura Sphere and Weather Ball on sun teams while it can 2HKO Raikou with Power Whip or 3HKO with Gyro Ball. Celebi can handle sets that rely on Weather Ball in rain for coverage against Ground-type Pokemon and do not run Signal Beam, and Latias can handle those plus the variants that run Weather Ball in sun.
There are several other Pokemon that make excellent checks. Dugtrio is one of the most dangerous Pokemon for Raikou to have to face. It can outspeed any non-Choice Scarf Raikou, trap it with Arena Trap, and knock it out with STAB Earthquake, so it is best to try to remove opposing Dugtrio before attempting a sweep. Heatran lacks reliable recovery to switch in constantly, but it can handle anything bar Aura Sphere and Weather Ball in rain and either hurt Raikou with Earth Power or phaze it out with Roar, possibly ending a Calm Mind sweep. Abomasnow can generally take any hit besides Aura Sphere and Signal Beam, while dealing considerable damage with Wood Hammer or Earthquake. Mamoswine also does not like Aura Sphere nor Weather Ball depending on the weather, but besides that it handles the BoltBeam combination with ease and can OHKO with Earthquake. Garchomp is a fast Ground-type that can outspeed Rash Raikou variants and threaten with its STAB Ground attacks. Even if Raikou is using a Timid nature, Garchomp, as well as Landorus-T, can easily check Raikou with Choice Scarf sets.
Raikou gets Volt Absorb from the Dream World, and it will be a great ability for Raikou once it is released. However, unless it is released alongside Weather Ball and Aura Sphere, it would be illegal with these two coverage moves. Still, the extra healing can be very useful for Raikou whenever it can switch into an opposing Electric-type attack, and it would definitely be more useful than Pressure.