I remember hearing that playing gen 5 OU is similar to rock paper scissors in the way that weatherless, sand, and rain fare against each other from one of BKC's videos. Anyone know of any posts elaborating this further? Not sure how to specifically look for it, but I'm interested in reading more.
Would be surprised if there were any posts on this, but I can summarise below. Note this is very very broadly speaking and there are many exceptions
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Rain vs Sand
The very simple answer is that Rain teams suffer more playing under Sand than vice-versa.
Rain teams tend to be built around defensive cores of Politoed/Ferrothorn/Tentacruel which utilise residual damage of Scald, Tox, hazards to support offensive mons. These mons tend to be quite reliant on Rain being up to do their job well, including:
- Keldeo (wants Rain for power + survivability of especially Sub sets)
- Thundurus-T (wants Rain for Thunder accuracy + survivability of especially Sub sets)
- Tornadus (wants Rain for Hurricane accuracy)
- Tentacruel needs Rain for Rain dish, again especially Sub sets
- Ferrothorn needs Rain to check mons with Fire coverage e.g. Latios, Dragonite
- and so on
Sand teams, on the other hand, are already loading up on Sand immunes so have that natural survivability advantage. However, outside nerfed Fire coverage, facing an increased power of water-type moves (which you are already prepared to face anyway when preparing for Scald) generally, there is otherwise no real disadvantage for Sand mons playing under Rain - some, such as Latios, Celebi, Rotom-W and their own Keldeo, actively enjoy playing under Rain so the opponent can be punished for actually having their preferential weather up. The closest a Sand Pokemon gets to being "nerfed" under Rain is SF Excadrill but this is not close to the nerf that Keldeo, Thundurus, Tornadus, Tentacruel face.
It goes a bit further than this - most Rains won't be able to fit Pursuit on and so they defensively struggle against Latios with hazards up. Teams that have Spike + Latios + a Magic Guard Psychic, which also overlaps as Scald/Keldeo prep, tend to be incredibly strong into Rain. The idea that Sand >>>> Rain comes from a time where Spikes + Latios/Reuniclus/Alakazam teams were the predominant Sand, and when Keldeo/Thundurus/Latios Rains were the most predominant Rain, and thats a MU in particular that can feel close to unwinnable for the Rain player.
major exceptions:
Rain abusers that happily play under Sand e.g. Mamoswine, Sub Jirachi, Garchomp can really punish Sand teams
Some Scizor Rains can be good into some Latios Sands due to pursuit
Sand teams that don't prepare well for Rain in an attempt to be better vs HO (Heatran + Scarf Latios stuff for example can be very frail into Keldeo)
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HO vs Sand
Hyper offense is really strong into Sand for a few reasons. The main upside of Sandstorm itself is in drawn out games with a residual damage focus, as there aren't really many proper offensive Sand abusers. HO aims to finish games in 20 turns or less which means there isn't much upside to having uncontested Sand - the upside of Sand is when the opponent brings another weather, not when the opponent brings weatherless offense.
More specifically, HOs capitalise on the defensive typings that most Sand teams stack in order to, well, be good vs Rain to begin with. The pool of glue mons that sand uses is mostly limited to:
- Sand immunes - Ttar (obv), Ferrothorn, Skarmory, Landorus-T, Gliscor, Garchomp, Excadrill, Gastrodon, Reuniclus, Clefable, Alakazam
- Scald immunes (some of which are needed for rain keldeo also) - Jellicent, Gastrodon, Clefable, Reuniclus, Breloom, Jellicent
- Spike immunes (if the sand doesn't have Excadrill it probably needs to minimise its hazard weaknesses): Gliscor, Landorus-T, Latios, Rotom-W
Find me reliable Quiver Dance Volcarona and Shell Smash Cloyster counterplay in that list. This is the unfortunate reality of building sand - a lot of the "safe" picks you want for residual damage immunity are set-up fodder for Cloyster and Volc and the remainder of your team can often fall to their power + coverage.
Another layer of complexity is that Sand teams have very few good Choice Scarf options, which means that revenge killing the likes of Volcarona or Dragonite can be tough. The Scarf options for Sand that are faster than Volcarona are like... Latios (Pursuitable and only good alongside another Tyranitar lure, so only works on a subset of sands), and Garchomp (grounded, spike susceptible, completely shut down by Skarmory). Other Scarfers like Excadrill, Landorus-T etc are good into Dragonite but they are also those Pokemon's worst sets. Tyranitar is a great Scarfer but revenge kills nothing boosted. The result is that, for a long time, a lot of sand teams were "cheating" speed control by using only Focus Sash Alakazam as a catch-all, 1-time revenge killer, therefore letting them avoid using a bad choice scarfer - however HO easily bypasses Alakazam by stacking multiple Pokemon that you'd rely on Alakazam to beat e.g. Volcarona, Dragonite, along with priority users Breloom, Cloyster, Scizor to easily overload the 1 time Sash use.
major exceptions:
Sand teams with Heatran or Keldeo (esp with ice coverage) tend to do well vs HO
Sand teams with Landorus-T can smartly use Intimidate to beat Dragonite / Cloyster / Breloom / Scizor
Sand teams with Jellicent can help keep up SR to limit Volcarona and Dragonite
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HO vs Rain
Rain is generally strong into hyper offense as uncontested Rain makes the abusers very difficult to handle, in contrast to Sand which finds it hard to leverage its uncontested weather in short games. Keldeo, Thundurus-T, Tornadus, Gyarados etc under rain are all HO killers, almost regardless of set, as the frail offensive Rain Pokemon often can't find set-up chances in front of Rain boosted Hydro, 100% accurate Thunder, 100% accurate Hurricane.
The defensive core under Rain also tackles the HO pokemon well. Defensive Politoed is strong into Cloyster and disrupts other set-up with Encore. Gyro Ball Ferrothorn is strong into Dragonite, which also gets its Fire Punch nerfed. Toxic Tentacruel tends to be good into Volcarona and Scizor.
Rain also has better access to choice Scarfers than Sand. Scarf Latios is more splashable on Rain and its faster than Volcarona + boosted Surf power. Scarf Keldeo is also a great option.
Major exceptions:
Without Gyro Ferrothorn or Ice Beam Politoed, Rain teams can actually be very bad vs Dragonite
Without Keldeo, Rains are at risk of losing to well-played Cloyster
Passho Volcarona
Sunny Day Magnezone
Some HOs run Abomasnow over a sweeper (normally dropping where Breloom would fit) which flips the Rain MU on its head
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Very very very general - the tier is not completely a rocks-paper-scissors of team selection but there are trends which lead to archetypes tending to be strong into others. There are loads of exceptions and the metagame changes a lot every year, some of the stuff above is already a bit outdated information