Hail
Atm, it is hail. The reason for this is that you do not make dedicated hail teams. The two hail mons, Alolan Ninetales and Arctozolt, just fit on a team. Take this for example, when you are building a dedicated rain team, you are almost always going to have Pelipper, Ferrothorn, Barraskweda, Seismitoad and a hurricane user. Hail is not like that. You do not build dedicated hail teams. Arctozolt can fit on the main wallbraeker slot on a team and Ninetales on the utility. There's also the fact that Arctozolt has stab on the boltbeam combination that only makes it much more deadly. This allows Zolt to be so effective against most of the standard defensive cores in Lando + Corvi + Pex / blah blah blah, that some teams can even lose to Arctozolt just from team preview
However, Arctozolt's dominance did lead to the rise of Ferrothorn which has added utility in fending off hail as well as threats like Koko and Weavile. Arctozolt is not also that mandatory on hail because Ninetales is another great Pokemon. Thanks to aurora veil, it can enable some Pokemon to have much better survivability. Mons like Garchomp, Volcanion, Lele, Weavile, blah blah blah, suddenly become difficult to kill thanks to the veil. In short, it is because of the flexibility of hail and Arctozolt's incredible wallbreaking that makes it the best weather
Sun
This might seem weird but after hail, I would say that sun is the best second best weather. Sun doesn't have the flexibility but it does bring a lot of firepower, pun intended. Something like specs eruption from Heatran or band v create from Victini just nukes even resists. Having said that, sun does have one glaring flaw, Garchomp straight up rips entire sun teams. If that wasn't enough, Dragapult is also having a field day just clicking shadow balls. These two are basically why I always recommend adding Mandibuzz to a sun team otherwise those two just eat your team alive
The reason why I would say sun is better than rain and sand is because their abusers have an easier time breaking thru stuff and other mons with fire coverage like mix Garchomp just appreciates the heat. As mentioned earlier, sun boosted fire type attacks just powers thru resists. This weather does need care to play and when building because it is really volatile if you're not used to playing it
Sand
For the third best weather, I would say it is sand. Normally, I would rank it the lowest but there is one quality that makes sand better, flexibility. After hail, sand is the one that has the most flexibility. On dedicated sand teams, all you really need is your Excadrill, Tyranitar / Hippowdon, and an answer to Rillaboom. The other three slots can basically be dedicated to wall breakers
The problem with this is that Excadrill *** sucks. It gets perpetually walled by Corviknight and it is not flinching its way thru metal birbs. It's no Jirachi after all. Don't even think about using Garchomp on sand as while dodging stuff might be amusing, it's a huge waste. There's also the fact that Landorus is gonna irritate Excadrill forever. Dracozolt might be a nice option but you do not want to use this thing as it is completely and utterly helpless against Hippowdon. Using all out physical Dracozolt and suddenly Landorus is annoying. Using mixed Dracozolt and Hippowdon straight up walls you for the rest of eternity
On the flip side, while sand abusers suck, both Tyranitar and Hippowdon are actually great Pokemon. Imo, sand is the best overall weather but since you're asking about the archetype, it falls this low. The reasoning being is that spdef Hippo can actually do a lot of stuff. It stuffs Koko and Zeraora, it disrupts hail, can reliably setup rocks, you can't setup on it thanks to whirlwind and is incredibly obnoxious to kill with neutral hits. Oh and it doesn't immediately die to Dragapult so that's another plus. Tyranitar itself is also another great mon and this is by virtue of its choice band set. It's really underrated but the only three mons that resist stone miss, Garchomp, Ferrothorn and Urshifu, aren't really that keen on switching into Tyranitar thanks to its very colorful movepool. It's unique set of resistances also allows it to switch into otherwise threatening mons like Blacephalon and Dragapult while simultaeneosly making Lele think twice about spamming its psychic stabs. Of course, Tyranitar does require a significant amount of support because it's so *** slow and is destroyed by all the grass, water, fighting and ground type moves running around. And don't forget that its main stab is called stone miss for a reason
In the end, the reason sand sucks isn't because of the setters but rather, its abusers are just garbage. Making dedicated sand teams just require too much support to pull off. Sand is basically the weather that doesn't have to be abused and you can even use it just to ensure opposing weathers can't overwhelm you. As I said eariler, it's the best overall weather since its setters are great mons but as an archetype, second worst
Rain
In the worst weather, I would say it is rain, specifically, dedicated rain teams. The reason for this is that dedicated rain teams have four Pokemon that are almost always the same with the fifth only having like two or three options. There's also the fact that Kyurem just straight up spams ice beam and there is nothing rain can do about it. Dedicated rain teams would usually consist of, as mentioned earlier, Pelipper, Barraskweda, Seismitoad, Ferrothorn and a hurricane user which is usually Tornadus. The sixth slot is the only free one but for maximum consistency, it would usually go to Scizor because of Kyurem and this leads to sacrificing another rain benefit which is perfect accuracy thunders
This kind of restrictive playstyle is why rain isn't that used. Deviating from that structure would leave your team vulnerable to a certain threat especially if you're new to the playstyle. For example, not having a hurricane user means that Rillaboom will destroy your team. Even if you have Scizor, it is not a guaranteed Rillaboom answer. If you don't use Ferrothorn then the very same gorilla will have an easier time since it can spam grassy glide with no consequence. Rain just offers so much that to fully abuse it, you are forced to use a certain set of Pokemon, which many players aren't willing to use
Without Mega Swampert and Greninja fueling rain teams, people just aren't willing to use such a restrictive playstyle. Seismitoad and Barraskweda are basically newborns compared to the level Swampert and Greninja are at
Lately, there are some experiments with using Volcanion on rain as a pseudo Kyogre but there haven't been enough discussions on it yet. While on the topic of Volcanion, the same also goes for sun teams since its stabs can overwhelm resists
tldr
Hail is best because of flexibility
Sun is second because of raw power
Sand is second worst because abusers suck
Rain is the worst because it is incredibly restrictive
Also, this is only considering the standard structure for the weather teams. You can tweak with them of course but that would require you to have really good experience with the archetype otherwise that one tweak just leaves you to get destroyed by a certain threat
You could make an argument that rain team is the second best but that is very debatable due to how restrictive it is. The same is also said for sun because it is very volatile but in the end, this is just their own inherent qualities
