Why hail?

With 3 other weather conditions available, you may be wondering why you would choose hail. Well, hail has one great advantage over Rain and Sun in that it causes residual damage, it does this even better than sand, as ice types are a lot rare than any of Steel, Ground or Rock. Of course, it has the great disadvantage of having only 1 type immune to it, which makes making a team rather difficult, hence the creation of this guide, which aims to explore different options available to a hail stall team.

Effects of hail

Before you start to look at possible members of your team, it's essential that you familiarise yourself with the full extent of hails powers. Below, the effects are listed in three categories; those that effect moves; Abilities that are activated & General effects.

Effects on moves

Blizzard - During a hailstorm, Blizzards accuracy increases from 70% to 100%, and as of Generation V, it ignores all accuracy and evasion modifiers, much like Aerial Ace.
Moonlight, Morning Sun & Synthesis - All of these healing moves only heal 25% of the users HP, as opposed to the usual 50%.
Weather Ball - Weather Ball changes type to ice, and doubles in base power from 50 to 100.

Abilities activated in hail

Ice Body - The user recovers 1/16th of their HP every turn, provided the prevailing weather condition is hail. This is a huge advantage on hail stall teams, as you are not only dealing damage but are also healing yours.
Snow Cloak - The user gains a 20% boost to their evasion, this is banned on Smogon, but if you are just going online this is a pretty awesome ability. If this is listed in the guide, an alternative is always present.
Forecast - The user changes type to Ice in hail; as the only user is Castform, this is not a great ability.

General Effects

Residual Damage - All non-ice types suffer a 1/16th loss to their HP, this effect is the core of most hail stall teams, and can be combined with toxic, and possibly even leech seed for a great amount of annoyance.

The Pokémon

Finally, we can look at the Pokémon you may want to include in your team. This list is by no means exhaustive, it just lists a few notable Pokémon you may want to include.

Abomasnow

Whether you like him or not, you most likely realise Abomasnow is a very important part of hail teams. His ability, Snow Warning, summons a permanent hailstorm. This means you don't need to keep setting hail up every 5-8 turns. Very useful.

Abomasnow with Leftovers
Snow Warning
Modest nature (+Special Attack, -Attack)
EVs: 252 HP / 252 Sp. Attack / 4 Sp. Def
Blizzard
Energy Ball
Focus Blast / Substitute
Toxic / Leech Seed

The first two moves are the best special STAB moves, Blizzard cannot miss due to Snow Warnings hail, and Energy Ball is the highest base power special grass move Abomasnow has available, and has a nice side effect of possibly lowering your opponents special defense. For your third moveslot, I would usually recommend substitute for a more stall orientated set, however if you would rather have more coverage, Focus Blast is an option as well. In your final moveslot, you want some form of status damage on your opposition, my personal preference is Leech Seed, especially with it only not working on grass, which is weak to Blizzard.

Walrein

Ah, my personal favourite hail team member. Very similar in strategy to Poison Heal Gliscor, Walrein is a great member on a hail stall team. A combination of an excellent ability (Ice Body), Decent Bulk, and an awesome design make this Walrus one your opposition may just smash their DS in frustration at.

Walrein with Leftovers
Ice Body
Calm nature (+Special Defence, -Attack)
EVs: 232 HP / 252 Defence / 24 Speed
Substitute
Protect
Blizzard / Surf / Ice Beam
Toxic / Aqua Ring

The focus of this set is the combination of Substitute, Protect and a handy 1/8th HP recovery every turn. After using Substitute and protect, walrein regains all HP lost through using substitute and the opponent will have lost 1/8th of their HP through hail damage. In your third moves lot, Blizzard is usually the best option as it can't miss in hail, however bearing in mind that Walrein will be out a long time, surfs PP can be invaluable. Ice beam can be a nice substitute, but this is only recommended when not running toxic, as the freeze chance is part of what makes it so attractive. In your final moveslot, Toxic is usually the best choice, as it speeds up the process of wearing the opposition down, however Aqua Ring is a nice choice as it allows a few more risky options when playing, for example if you think they'll switch, you can use blizzard and if they don't, you can take the hit and heal it across a few turns.

Mamoswine

It's a mammoth. You can't fail to love it. Mamoswine is definitely not for stalling, however that doesn't mean he shouldn't have a place in your hail stall team. It is very effective when used to break opposing stall, and after much play testing I have found him most effective in eliminating opposing Weather inducers.

Mamoswine with Choice Scarf
???
Adamant nature (+Attack, -Special Attack)
EVs: 4/252/0/0/0/252
Earthquake
Superpower
Stone Edge
Icicle Crash

The only weather this guy struggles with is rain; Tyranitar is OHKO'd with Superpower, Ninetales by Earthquake and Hippowdon is 2HKO'd by Icicle Crash (physically defensive Smogon set). Politoed is 2HKO'd by Earthquake, but the problem is he will likely KO first with Hydro Pump, so it's not advised to go against Politoed with Mamoswine. Don't think this is Mamoswines only uses though, he can handle a great number of threats: Dragonite, Salamence, Hydreigon, Haxorus, Metagross, Just to name a few. If you want a little bit of offence in your stall team, Mamoswine can make a great addition. On a side note; if you are allowing snow cloak in your game, that makes a great choice for Mamoswine, allowing him to avoid the occasional hit, if you do have this he is able to go against Politoed, as Hydro Pump is fairly likely to miss (still very risky, however, and there are better alternatives).

Reuniclus

Reuniclus is a great idea on stall teams, Magic Guard prevents it taking hail damage but it doesn't have the weak defensive typing ice has. A Reuniclus in a hail stall team runs an entirely different set to Trick Room reuniclus; it has to focus more on slowly eliminating the opposition.

Reuniclus with Leftovers
Magic Guard
Bold nature (+Defence, -Attack)
EVs: 252 HP / 252 Defence / 4 Special Defence
Substitute
Pain Split / Recover
Toxic / Thunder Wave
Psychic / Psyshock

Substitute and Pain Split work fantastically well together, however Reuniclus' high HP makes it slightly ineffective, so if doing damage isn't a large problem, then recover is a better option for recovery. The choice of status move depends on your play style. Toxic is highly recommended if you choose recover over pain split, as it will do much needed damage. Psychic/Psyshock are there so that Reuniclus isn't complete taunt fodder, but the choice of which you want is purely based on whether your team strugles on the Ohysical or Special side more.

Forretress

One of the premier Stealth rockers in the game; Forretress holds a key ability in Overcoat, allowing a great defensive typing into a hail team without taking damage from hail. One of his biggest advantages is having access to all 3 Entry Hazards and Rapid Spin!

Forretress with Leftovers
Overcoat
Relaxed nature (+Defence, -Speed)
EVs: 252 HP / 252 Defence / 4 Special Defence
Rapid Spin
Stealth Rock
Spikes / Toxic Spikes
Gyro Ball / Volt Switch

Rapid Spin is most of the reason you would take Forretress, as Stealth Rock can destroy hail teams. Stealth Rock is a very easy entry hazard to set up, and so is always recommended. The choice between Spikes and Toxic Spikes depends on personal preference, Toxic spikes will save you a lot of time using toxic later in the battle, but Spikes does more damage straight away. Gyro Ball is normally the better damaging move, but Volt Switch has the appealing side effect of getting Forretress out of trouble.

Glaceon

With a ridiculously powerful Blizzard, you may wonder why you'd put Glaceon on a stall team. The answer is, once the opponent sees it stalling, they'll be less likely to suspect +special attack nature, or special attack evs. Then at the right time, you launch an absurdly powerful Blizzard!

??? Pokémon with Leftovers
Ice Body
Modest nature (+Special Attack, -Attack)
EVs: 252 HP / 252 Special Attack / 4 Special Defence
Blizzard
Substitute
Toxic
Protect

Start by proceeding as Walrein does; Glaceon can use this same strategy. It has a slight disadvantage over Walrein in that it doesn't have the natural bulk to take hits, however it does have a much stronger Blizzard, capable of OHKOing Arceus (depending on type, of course)

Conclusion

This article has shown only some of the options available to hail teams, but some important things to remember:

Other Weathers - Whilst hail should be the dominant weather, you must remember other weathers are used, so keeping a spare thunder in your team just in case there is a Politoed isn't a bad idea. Also, remember to have someone with Hail alive at all times, so that you can set it up again.
Hail Immunity - Most members on your team should be immune to hail, but this doesn't mean all of them do. Some good Pokémon that function in hail are: Swampert; Spiritomb; Bronzong & Flygon.

So, that's it for Hail Stall, I hope this guide helps you to choose some good contenders for your hail team!