Rain in BDSP OU has had a wild ride, starting off so dominant that Drizzle had to be completely banned from the tier, to then falling out of favour so incredibly hard that it felt like little more than a gimmick that only lower ladder players would run, to seeing a small resurgence during 2024 as a respectable, yet still fringe and match-up fishy, playstyle. But with this slight uptick in rain there has also been a slight uptick in players, especially those less familiar with the tier, who find it difficult to manage. While it is true that rain can be a bit of a teambuilder check, there are more than enough avenues one can take while in the builder in order to have a playable matchup into rain teams.
Basic Rain Structures
To understand how to beat rain it's important to first understand how rain teams are made and how they generally function.

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Volbeat and Kingdra are the two mons which are absolutely mandatory on any serious rain team. Volbeat is the main rain setter for these teams thanks to Prankster Rain Dance guaranteeing rain can go up in most situations while also boasting other good utility such as U-turn pivoting, Thunder Wave for sudden speed control, and Encore for disruption tactics. Kingdra meanwhile becomes one of the most devastating threats in the metagame when under rain, threatening OHKOes on many neutral targets with its Water STAB and outspeeding even the fastest of scarfers such as Infernape and Latias.

Rain teams won't settle with just Volbeat as their weather setter, so they'll employ the services of Mew and friends to act as secondary rain setters as well as the Stealth Rock setter for the team. These mons will usually lead off early game in order to set hazards and rain and then killing themselves for momentum, though they can also make an appearance in the mid-game to set up rain if need be. Mew is the most common option, as it can set hazards, deny opposing hazards with Taunt, and then use Explosion to gain momentum while rain is up. Azelf accomplishes the same thing as Mew but with higher speed and damage output at the cost of lower bulk, which can be particularly rough on rain teams who want ideally hazards
and rain set up in the early game. Jirachi is by far the least common of these options but it has some nice traits. While it lacks Taunt and Explosion, its access to U-turn and Healing Wish can prove useful for rain teams, offering them extra pivoting support and allowing one of their offensive threats to be fully healed in a pinch.

More offense is still required on rain teams, so strong Swift Swim users beyond just Kingdra are staples on rain teams. Ludicolo offers a uniquely threatening choice on rain, as it's a Swift Swim user blessed with STAB Giga Drain that directly threatens bulky water types who could withstand its Water STAB while also healing off any Life Orb recoil. Unfortunately for Ludicolo, it cannot afford to run a Modest nature or else it is outsped by Choice Scarf users like Garchomp and Infernape while under rain, so a Timid nature is required, though it remains slower than Scarf Latias by just a single point. Qwilfish, on the other hand, is a strong physical sweeper who can break past bulky Grass types with its Poison STAB and trade with anything in a pinch with Explosion. Lastly, Poliwrath can sweep while under rain with a Belly Drum set, although it is pitifully weak without a boost with this issue being further compounded by requiring a Jolly nature much for the same reasons as Ludicolo.

Azumarill and Crawdaunt both offer the same thing for rain teams, a strong physical Water breaker with priority. They can run their classic Choice Band sets, or other sets of their choosing (Belly Drum for Azumarill, mixed for Crawdaunt). Not much to say here.

Two other common choices on rain teams. I wasn't really sure on where exactly they would go since they don't fall under any other category and calling them other options or filler feels wrong. I guess we could put these under "pivots for rain teams". As for the mons themselves, Scizor doesn't benefit at all from rain directly but it offers loads of defensive utility for rain teams, such as a Latias and Weavile answer with longevity, while allowing rain abusers to safely come in thanks to U-turn. It can act as an extra rain setter for these teams with a more defensive spread or it can go on the offensive and run Swords Dance with attack investment, taking advantage of rain tearing through its main checks for an easy late game sweep. Raikou on the other hand is much more simple, it benefits from rain thanks to Thunder becoming a guaranteed hit under rain as well as Scald getting an extra boost in power for dealing with Ground-types. Greatly threatening bulky Water-types is nice for rain teams as those can be a hassle to break through on occasion, and Volt Switch lets it keep momentum when it cant make clear progress.
Other miscellaneous options can be considered when building rain. Pretty much any offensive Water-type can benefit in some way from being used on a rain team, though effectiveness can vary drastically between some options.
In practice you'll end up with something looking like these teams, the first one being from the sample team thread and the second being my own creation. Unfortunately I don't have any others on me as of writing this so this is all I can show for now.
https://pokepast.es/d9328f70cad64849
https://pokepast.es/29b7e1d9eb4e258e
Withstanding The Weather
With a basic understanding of rain teams and how they're built, it's time to start looking at your options for being able to withstand the onslaught of aquatic offense that rain teams bring to the table.
The Walls

(with storm drain)
Simply put, the best defensive answers to rain teams there are in the metagame. While they are not perfect against all rain abusers, their ability to cover major portions of these teams' offense and stick around for longer games helps ease the rain matchup significantly for any team that decides to pack them.

The blob that walls special attackers walls a team style that consists primarily of special attackers. More news at 11. But seriously, Blissey's immense special bulk and access to support moves like Thunder Wave to cripple the enemy's offensive threats and Stealth Rock to punish switches from the opponent make it extremely difficult for rain teams to remove easily. Fits best on balance and stall, but can potentially see use on BO teams.

Specially defensive Celebi is a solid wall against rain teams for offense and BO teams, being able to withstand strong Water moves while not fearing Ice, Grass, or Electric coverage. STAB Giga Drain and Recover can help keep Celebi healthy while options like Stealth Rock, U-turn, and Thunder Wave offer valuable team support.

Milotic can be a massive pain for rain teams that lack mons like Ludicolo or Raikou, since it can eat up rain-boosted Water moves with ease and recover them off safely. Once it hits the field there won't be many ways to force it off, as even setup attempts can be thwarted with Haze. Fits best on bulkier team styles such as balance and stall.

Though Tangrowth's poor special bulk can make it seem worthless against rain, its absurd physical bulk is put to use against rain's physical threats, and in a pinch it can even take rain-boosted Hydro Pumps from the likes of Kingdra. Knock Off, Sleep Power, and Leech Seed are all great ways for Tangrowth to punish switches from rain teams and Regenerator lets it stick around even if it takes a big hit. Tangrowth is almost always paired with something that can sponge special attacks to boot, so it won't facing the storm alone. Fits on teams ranging from BO to stall.

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The Slowtwins may struggle in BDSP OU but they can prove quite useful against rain teams. Slowking boasts the better matchup of the two thanks to its much higher special bulk letting it withstand rain's many special attackers more reliably. Slowbro, on the other hand, can struggle to take multiple rain-boosted Surfs and Hydro Pumps, but it can switch into them in a pinch while more reliably answering the physical attackers like Qwilifsh and Azumarill. Regenerator and Slack Off give them good longevity against these teams and with Thunder Wave they can slow down rain's offensive threats, making them easier to manage. Calm Mind can also aid in withstanding the rain abusers while becoming a potential win condition at the same time. Fits best on balance and stall, can see some use on BO.

Storm Drain Gastrodon hard walls every rain abuser aside from Ludicolo and the physical breaker duo of Azumarill and Crawdaunt. Qwilifsh can lure Gastrodon in and remove it with Explosion on the switch but that requires a hard read and Gastrodon may not even be a team's immediate answer to Qwilifsh, resulting in a large potential loss for little gain. Like many of the other bulky water options listed so far, it fits best on balance and stall teams.
Softer Checks




These are options which can be solid against rain teams, but who are less reliable than the mons listed above for a variety of reasons, whether it be lack of recovery, less-than-stellar bulk, lack of resistances, etc.. Still, though they may have some issues, they're still good enough for most teams as ways to deal with rain.

Washtom is a metagame staple that anchors many offense and BO teams thanks to its long list of valuable traits. Many of these same traits can help it stave off Rain teams for its partners, especially with a specially defensive spread. STAB Volt Switch is nice for chipping away at the opposing team and helping with positioning, while Protect can help stall out rain turns and give Washtom extra Leftovers recovery. If running Thunder Wave, it can greatly cripple the Swift Swimmers by cutting them off from their most valuable trait: their unparalleled speed. Physically defensive spreads can help check the physical rain abusers like Qwilfish, Azumarill, and Crawdaunt, with Will-O-Wisp ruining their damage output. Choice Scarf sets can also prove useful early game, though there will be more on that later.

Starmie's Water resistance and access to Recover make it decent at handling strong rain-boosted moves in 1-on-1s, though it has difficulty actually switching in to said attacks. A large part of Starmie's utility against Rain teams comes from its early-game utility, which I'll elaborate more on later.

Solid natural bulk and useful resistances with access to Recover makes Latias decent at handling Rain teams, though she must be wary of STAB Draco Meteor from Kingdra as well as Ice Beam coverage. Her strong STAB moves can put massive dents into Rain teams and/or force a switch which can be taken advantage of. Choice Scarf variants outspeed Ludicolo even under rain and Calm Mind can make Latias difficult to break for the special attacking threats.

Suicune's solid natural bulk, Water resistance, and Pressure ability can prove troublesome for Rain teams. Though it is prone to being worn down due to a lack of recovery aside from Leftovers, Suicune can make use of Protect to gain more passive recovery, stall out Rain turns, and burn even more PP thanks to Pressure. Calm Mind can also be useful if there is an opportunity to use it, as it makes Suicune extremely difficult to break without a strong physical rain abuser or Ludicolo/Raikou.

Less valuable than Celebi against Rain teams due to its lack of a Water resistance, which makes it unable to pivot in reliably against rain-boosted Water moves. However it can still take hits well enough to where it can spam Roost in 1-on-1s in order to stall out Rain turns.

Empoleon's typing is extremely useful defensively against Rain, resisting Water, Dragon, and Fairy; being neutral to Grass; and possessing an immunity to Poison. Its lack of recovery and general passivity can be a bit of an issue, as it can be worn down quickly if it isn't careful, but it can still make its mark with hazard utility and phazing options.

No Water resistance and poor special bulk, but with solid physical bulk, Skarmory can check the physical rain threats in a pinch and phaze them out. Spikes can also help wear down Rain teams quickly, and Sturdy can let Skarmory take a strong special hit in a pinch.
One-and-Dones
These are mons who can be useful defensively against rain, but usually are only able to take one strong hit before being unable to take any more hits. This makes them useful more so as revenge killers and pivots into weaker moves than walls that can take a beating over the course of a game.

Though Roserade's bulk isn't particularly amazing, especially when having to face off against rain-boosted Water moves, it's able to take at least one hit with ease and cripple the opponent with status (usually sleep) or set up Spikes, which can wear down the opposing team quicker for your own threats to clean up late-game. It can also pivot into Ludicolo's STAB moves decently well, as Hydro Pump isn't favoured to 2HKO even with Stealth Rock and Giga Drain does next to nothing thanks to Roserade's 4x Grass resistance. Ice Beam can sting though.

Azumarill's fantastic typing is betrayed by its lack of recovery and good-but-not-great bulk leaving it vulnerable to being worn down quickly if it isn't careful. Defensively speaking, this means it can usually only take one big hit, though its immunity to Draco Meteor and resistance to Ice Beam can be helpful in a pinch against Kingdra. However, Azumarill can be quite potent offensively against rain teams, as they can have trouble withstanding its powerful Play Roughs, with their most common resists being Qwilfish (2HKOed and no recovery) and Scizor (can't take rain-boosted Waterfalls). Aqua Jet isn't particularly useful in most situations, since most rain abusers resist Water, but it can be used to pick off weakened threats in a pinch.
Slowing Down The Storm
The early-game for Rain teams heavily revolves around setting up Rain and hazards as early as possible, which means that Volbeat or Mew will often lead off in order to execute their gameplan. Though this can be effective, it can be equally abused by the opposing team, who can anti-lead these mons to try and prevent the Rain team from gaining an uncontested lead.
Offensive anti-leads

These anti-leads use their offensive potential to greatly threaten Rain teams while they're setting up their weather and hazards.

The tier's Dark-types are all solid anti-leads against Rain teams, as they reliably OHKO Mew with their Dark STAB and can't be affected by Volbeat's Prankster due to their typing. They all possess advantages and disadvantages, so it would be best to quickly go over them.

Weavile is the fastest of the Dark-types and the fastest mon as a whole in the tier, which means that it can outspeed and OHKO Mew with Throat Chop before it gets the chance to set up hazards or rain. It's unable to OHKO Volbeat however, but a 2HKO is still plenty valuable, as it means that Volbeat will either have to take another attack and faint, or one of the rain team's other mons will need to hard switch into Weavile, which isn't impossible, but it will often leave a lasting mark that will be easy to take advantage of later. The need for a second hit in order to KO Volbeat also means that Rain turns are being wasted trying to withstand Weavile. Lastly, Ice Shard can be used in a pinch to pick off weakened Rain threats.

Crawdaunt is so frail that despite its Water resistance it still can't take rain-boosted Water moves, leaving it to make its impact in the early-game before the rain abusers can hit the field. Though it is slower than both Mew and Volbeat, it reliably OHKOes the both of them with Knock Off; a Choice Band is needed in order to OHKO the latter, however. Picking up an immediate KO on a Rain setter is immensely valuable, as you limit the Rain team's options for later in the game drastically by doing so. It's also worth noting that Mew cannot set both hazards and Rain against Crawdaunt, since it would be KO'd immediately after it sets one, meaning that oftentimes Mew will have to either forego hazards entirely or wait until much later in the game to set them up. If Crawdaunt is somehow still around for later in the game, Aqua Jet can be used to pick off weakened threats.

Though it is tiered UU, Tyranitar is still viable enough in OU to be mentioned in this post. It is also arguably the best Dark-type against Rain teams, as although it is weak to Water, its Sand Stream ability can completely eliminate Rain whenever it hits the field while also having solid enough bulk to tank boosted Water moves in a pinch. What was said about Crawdaunt vs Mew/Volbeat also applies to Tyranitar, though Stone Edge is preferable if you wish to OHKO Volbeat.

Heracross's STAB Megahorn rips through Mew (barring a miss) and with Guts you deter Volbeat from attempting to Thunder Wave you turn 1. You don't OHKO Volbeat without a Guts boost so what was mentioned prior about wasting Rain turns while threatening a KO or massive damage on a rain abusers still applies here.

Shreds through Volbeat with STAB Brave Bird and you 2HKO Mew as well. Since Staraptor has poor longevity regardless there isn't much to lose in using it to break open holes early-game against Rain teams. Everything on Rain teams is 2HKO'd at minimum by Brave Bird (bar the rare Jirachi), which means that any attempts at preserving Mew will backfire immensely.
Hazard setter anti-leads
Rain teams play at such a fast pace that they don't bother running hazard removal, since it would waste precious turns that could be instead spent on brute forcing their way through the opponent. As such, fast hazard setters like Garchomp, Infernape, and Azelf can set up Stealth Rock before the likes of Mew can use Taunt to deny them. With no removal to speak of, those hazards will stay up the entire game and chip away at the rain team, making them easier to pick off with priority and faster threats when rain isn't active.
Disruptor anti-leads

There is no real reason for Rotom formes to keep their Choice Scarf against rain teams. When rain is active the Swift Swimmers outspeed them handily, and when it isn't active Rotom will outspeed them regardless. As such they can Trick away their Scarf turn 1 with no real repercussion, crippling the opponent. They may even take away the Damp Rock from Mew or Volbeat. Choice Specs can also be Tricked away but since you'll be slower than Mew it can set up weather or hazards beforehand.
Progress denier anti-leads
Starmie may be a bulky Water with less-than-stellar bulk, but its high Speed and access to Rapid Spin make it extremely useful in the early-game against Rain teams. The Volbeat matchup can be a bit iffy, as Starmie can't do too much aside from chip away at it with Scald, but Starmie can completely shut down Mew/Azelf leads. Rapid Spin denies them the ability the set Stealth Rock, so the more turns the opponent spends trying to set them up against Starmie, the more time they're wasting, especially if they tried to set up Rain in the meantime. The only difference between the Mew and Azelf matchup is that Starmie needs to click Rapid Spin turn 1 against Azelf in order to outspeed it and deny it the ability to block Rapid Spin with Explosion.
Turning The Tide
Once the game starts nearing its end, you're probably going to want to amp up your offensive pressure in order to finish off the Rain team before it can finish you off for good.
Priority users

Strong priority is extremely useful against Rain teams because it bypasses their immense Speed stats and prevents them from going on a rampage for free.

Multiscale Dragonite is a classic anti-offense option, being able to tank a multitude of strong attacks while at full health and use it as a setup opportunity. Dragonite's Water resistance is helpful against Rain since it lets it withstand those strong, boosted attacks while setting up. Extreme Speed is extremely strong, letting Dragonite pick off Rain abusers once they've taken enough chip damage. Choice Band sets are also useful against rain, offering immediate strength at the cost of being unable to set up for an endgame sweep.

Lucario can basically sweep Rain teams after a Swords Dance thanks to Extreme Speed, though hazard chip is still necessary for some rolls. However, because of its lack of bulk and Water resistance, Lucario can have difficulty setting up. Good opportunities to set up would be taking advantage of a Kingdra locked into Draco Meteor or Ice Beam, or setting up against a pivot like Scizor.

Choice Band sets can provide immediate pressure with Technician Mach Punch, while Swords Dance sets can sweep similar to Lucario. Breloom's frailty gives it difficulty in finding setup opportunities, even with a Water resistance.

A more niche anti-offense option, especially when compared to Dragonite, but it offers strong priority in Extreme Speed in order to help deal with Rain teams. As a Fire-type, which is usually afraid of strong Water-based offense, this is a nice trait to have.
Bulky setup

Bulky setup sweepers can prove useful against Rain by being able to withstand the attacks thrown their way and using it as an opportunity to set up or retaliate with big damage. I've already went over these examples before, so I'll keep it quick.

Latias offers immense power against Rain teams that is backed up by solid bulk, useful resistances, and reliable recovery. She must be wary of Draco Meteor and Ice Beam but otherwise she can take boosted Water moves and threaten out Rain abusers. Calm Mind makes Latias even more difficult to break past as well as making her an even greater threat.

Calm Mind Suicune is well-known for its ability to close games quick with its impressive bulk and Pressure, alongside Substitute + Protect granting it opportunities to safely set up. Though Scald does little damage to common Rain abusers, the burn chance and many opportunities Suicune can find to use the move will help chip away at the opposing team. Pressure in conjunction with Protect and Substitute can also help burn through the PP of some of Rain's more dangerous attacks, such as Kingdra's Hydro Pump.
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One thing I would like to point out with all the mons mentioned throughout the post is that they're all viable options in the tier that have many reasons to be put onto a team beyond their matchup against rain teams. This means that it isn't necessary to go looking for extremely fringe lower tier options in order to handle Rain. I would also like to stress that I didn't bother listing every single Pokemon and strategy that can be used to combat rain effectively, otherwise this post would be an absolute mess (as if it isn't already). Pokemon that you might have not initially considered to be of use against rain can help stave it off if you play your cards right. And lastly, I want to highlight that last bit again:
you can have the tools to beat rain, but ultimately it is up to you to wield them effectively in order to beat it reliably. There is rarely, if ever, a way to win based purely on matchup, so it is best not to get complacent when playing against rain, or any play style for that matter.