In defence of sun
I've been playing nothing but sun for a few months now and I think it's a lot better than most people think. I have never played a truly unwinable matchup and unless I get really unlucky, I know where I misplayed when I lose games. Almost every counter to sun is very manageable and I don't think 1 mon can completely wall a sun team. In this post I want to cover every "counter" people bring up when discussing sun and how to beat it. If I missed anything (which I probably will) feel free to respond. Lastly I didn't include any Pokemon from B- or below since most of these are really uncommon, bad or speak for themselves and I don't want this post to be extremely long (like it isn't right now lol).
This is the team I've been running, peaking around 1600. After a lot of tweaking, I think this is the best sun team since it covers almost every counter in the meta right now but of course I'm open for changes. This is also the team I'm calculating with and considering when discussing counters to sun.
The waters
Carvanha isn't really a thread to this team. Mach punch kills it so you can switch Timburr in on protect. If you lose Timburr you can go for the speed tie with Charmander and kill with weather ball or kill it with Ponyta if you didn't get chipped
196 SpA Solar Power Charmander Weather Ball (100 BP Fire) vs. 0 HP / 36 SpD Carvanha in Sun: 19-23 (100 - 121%) -- guaranteed OHKO
196+ Atk Life Orb Carvanha Crunch vs. 0 HP / 0 Def Eviolite Ponyta: 12-16 (57.1 - 76.1%) -- guaranteed 2HKO
Mareanie is a tough one, it pretty much requires sun to be up, Diglett with sash or a knock of from Timburr
156 Atk Diglett Earthquake vs. 116 HP / 180+ Def Eviolite Mareanie: 14-18 (60.8 - 78.2%) -- guaranteed 2HKO
With sun up it can live scald and 2hko it but you're risking a burn.
12 SpA Mareanie Scald vs. 36 HP / 76 SpD Diglett in Sun: 6-8 (33.3 - 44.4%) -- guaranteed 3HKO after burn damage
If you do get burned it should leave you at 10hp which is enough for final gambit to kill.
You can maybe cheese with sleep on Vulpix but it's extremely unreliable.
Frillish is pretty tough to deal with but definitely doable. Scarf water spout Frillsh which has become pretty populair doesn't matchup well into sun since it can't reliably ohko anything and is pretty useless after losing hp. Tank Frillsh is a lot harder to deal with but if you can knock it off it dies to solar blade Ponyta, and can't reliably swap into weather ball anymore.
76 Atk Ponyta Solar Blade vs. 156 HP / 116+ Def Frillish: 22-26 (91.6 - 108.3%) -- 50% chance to OHKO
196 SpA Solar Power Charmander Weather Ball (100 BP Fire) vs. 156 HP / 156 SpD Frillish in Sun: 11-13 (45.8 - 54.1%) -- 59.4% chance to 2HKO
Even with Eviolite you should be able to force it out on 50-40 hp if you have more than 3 sun turns
76 Atk Ponyta Solar Blade vs. 156 HP / 116+ Def Eviolite Frillish: 14-18 (58.3 - 75%) -- guaranteed 2HKO
Also frillsh has some laughable attack calcs into sun itself so its basically a sitting duck who can't do much.
0 SpA Frillish Scald vs. 0 HP / 76 SpD Eviolite Ponyta in Sun: 2-6 (9.5 - 28.5%) -- 0% chance to 4HKO
0 SpA Frillish Scald vs. 52 HP / 0 SpD Vulpix in Sun: 8-12 (38 - 57.1%) -- 0.4% chance to 2HKO
Staryu is probably the easiest water type to take care of after maybe Carvanha. Technically you have 2 Staryu sets but they're extremely similar defensive Staryu runs rapid spin instead of psychic, a little hp evs instead of spattack and scald instead of hydro, these changes don't really matter but fyi I used offensive Staryu in the calcs since it is more common. Staryu pretty much dies to solar blade Ponyta after the slightest of chip and it can't really touch you when sun is up.
236 Atk Ponyta Solar Blade vs. 0 HP / 156 Def Eviolite Staryu: 16-20 (84.2 - 105.2%) -- 6.3% chance to OHKO
116 SpA Analytic Staryu Hydro Pump vs. 0 HP / 76 SpD Eviolite Ponyta in Sun: 12-14 (57.1 - 66.6%) -- guaranteed 2HKO
I usually flame charge into solar blade since its the most reliable and it leaves your ponytail with that nice speed boost.
Vulpix also lives hydro so you can throw of an energy ball and kill with Charmander if you lose Ponyta
116 SpA Staryu Hydro Pump vs. 52 HP / 0 SpD Vulpix in Sun: 14-18 (66.6 - 85.7%) -- guaranteed 2HKO
196 SpA Vulpix Energy Ball vs. 0 HP / 0 SpD Eviolite Staryu: 10-14 (52.6 - 73.6%) -- guaranteed 2HKO
196 SpA Solar Power Charmander Weather Ball (100 BP Fire) vs. 0 HP / 0 SpD Eviolite Staryu in Sun: 9-12 (47.3 - 63.1%) -- 96.5% chance to 2HKO
The trappers
This kinda speaks for itself but if my opponent has trapinch or Diglett I always lead Timburr since it is a pretty free knock off, and with a slow u-turn Larvesta it isn't hard to get sun up without leading Vulpix.
Diglett is a lot more annoying, if it's holding a sash or scarf it can revenge kill Charmander, Vulpix and Ponyta. However sash only takes 1 sucker or mach punch to break and scarf is so uncommon I've only seen it once. Also if you don't get unlucky you can live earthquake and kill Diglett with solar blade (as long as its air balloon or eviolite).
156 Atk Diglett Earthquake vs. 0 HP / 0 Def Eviolite Ponyta: 18-24 (85.7 - 114.2%) -- 6.3% chance to OHKO
I wouldn't really count trapinch as a counter since Charmander ohko's it with overheat/fireblast. The only annoying thing trapinch can do is trap Vulpix, but even that it doesn't do 100% reliably.
196 SpA Vulpix Overheat vs. 0 HP / 76 SpD Eviolite Trapinch in Sun: 18-22 (85.7 - 104.7%) -- 43.8% chance to OHKO
Priority
Mienfoo fake out isn't really a counter to Charmander, it deals way to little dmg, dies to weather ball at 100% and if Charmander gets low, Larvesta is a pretty free swap.
0 Atk Mienfoo Fake Out vs. 44 HP / 12 Def Charmander: 5-6 (23.8 - 28.5%) -- 22.8% chance to 4HKO
196 SpA Solar Power Charmander Weather Ball (100 BP Fire) vs. 0 HP / 36 SpD Eviolite Mienfoo in Sun: 19-24 (90.4 - 114.2%) -- 81.3% chance to OHKO
The only threatening move Mienfoo can run is stone edge since is kills Larvesta.
0 Atk Mienfoo Stone Edge vs. 76 HP / 236+ Def Eviolite Larvesta: 20-28 (86.9 - 121.7%) -- 93.8% chance to OHKO
Discussed before, sucker doesn't really hurt Charmander
156 Atk Diglett Sucker Punch vs. 44 HP / 12 Def Charmander: 7-9 (33.3 - 42.8%) -- guaranteed 3HKO
Sash Diglett revenge kills Charmander and Vulpix but as long as you break the sash it can't touch you.
I've never really had an issue with Pawniard. Timburr, who should be on the majority of sun teams because of defog, destroys pawn with mach punch, and even without Timburr, Charmander can still dish a few weather balls out after a pawn sucker punch:
156 Atk Pawniard Sucker Punch vs. 44 HP / 12 Def Charmander: 12-15 (57.1 - 71.4%) -- guaranteed 2HKO after Solar Power damage
Sash rocks can't do anything against Timburr so its really easy to keep rocks off. just remember the defiant boost from defog.
Grookey obviously has a terrible matchup against sun. If the opponent doesn't run any trappers, you can almost always swap in Ponyta on Grookey without getting punished. Eviolite grassy glide only deals around 30% to your team and the terrain is nice recovery.
Grassy seed grookey with +2 still can't really touch your team.
+2 236 Atk Grookey Grassy Glide vs. 44 HP / 12 Def Charmander in Grassy Terrain: 14-17 (66.6 - 80.9%) -- guaranteed 2HKO after Grassy Terrain recovery
+2 236 Atk Grookey Grassy Glide vs. 0 HP / 156 Def Eviolite Ponyta in Grassy Terrain: 8-9 (38 - 42.8%) -- guaranteed 3HKO after Grassy Terrain recovery
First impression Trapinch doesn't touch your team ever unless you're super low, and as previously stated gets ohko'ed by Charmander.
36+ Atk Trapinch First Impression vs. 44 HP / 12 Def Charmander: 5-6 (23.8 - 28.5%) -- 93.8% chance to 4HKO
Timburr is not the easiest to deal with since you can't reliably ohko it with weather ball if it runs any spdef or hp ev's (overheat and fireblast do kill though)
196 SpA Solar Power Charmander Weather Ball (100 BP Fire) vs. 0 HP / 156 SpD Eviolite Timburr in Sun: 19-24 (79.1 - 100%) -- 6.3% chance to OHKO
Also Timburr's mach punch hurts a lot with iron fist
196+ Atk Iron Fist Timburr Mach Punch vs. 44 HP / 12 Def Charmander: 9-12 (42.8 - 57.1%) -- 12.1% chance to 2HKO
The really scary Timburr set is bulk up though. If Timburr gets +3 up you lose the game, he ohko's your special attackers with mach punch and gets too bulky for physical attackers. If he gets +2 up and your Vulpix or Charmander isn't 90+ hp you lose so you have to be really careful. +1 Timburr also 2hko's your specials so you can't swap them in after the first bulk up without risking mach punch on the swap. It's definitely possible to deal with bulk up though. If Timburr sets up on Larvesta you can u-turn to your specials. If you flare blitz into bulk up with sun you can kill it with another.
236 Atk Ponyta Flare Blitz vs. 0 HP / 156 Def Eviolite Timburr in Sun: 18-22 (75 - 91.6%) -- guaranteed 2HKO
236 Atk Ponyta Flare Blitz vs. +1 0 HP / 156 Def Eviolite Timburr in Sun: 12-15 (50 - 62.5%) -- guaranteed 2HKO
Or if really necessary, you can sacrifice something like Diglett with final gambit to get the free switch.
Other threads
`Porygon is here because defensive Porygon is rlly hard to deal with. It walls Charmander and completely shuts it down with thunder wave.
196 SpA Charmander Overheat vs. 156 HP / 156+ SpD Eviolite Porygon: 9-12 (36 - 48%) -- guaranteed 3HKO
It also has recover which makes it tricky to chip down. The scariest thing about this set though is trace, If your opponent traces your flash fire it becomes pretty scary. Timburr can't ohko it with drain punch without knocking off first but thunder wave can fuck you over with para hax.
196+ Atk Iron Fist Timburr Drain Punch vs. 156 HP / 196 Def Eviolite Porygon: 14-20 (56 - 80%) -- guaranteed 2HKO
Agility is also scary because it barely outspends and kills charmander with the same recovery defensive Porygon has
+1 236+ SpA Porygon Tri Attack vs. 44 HP / 0 SpD Charmander: 22-27 (104.7 - 128.5%) -- guaranteed OHKO
However, it does get 2hko'ed by charmander and Timburr ohko's it with a little chip damage
196 SpA Solar Power Charmander Weather Ball (100 BP Fire) vs. 0 HP / 0 SpD Eviolite Porygon in Sun: 18-22 (78.2 - 95.6%) -- guaranteed 2HKO
196+ Atk Iron Fist Timburr Drain Punch vs. 0 HP / 36 Def Eviolite Porygon: 18-24 (78.2 - 104.3%) -- 6.3% chance to OHKO
Scarf Porygon is pretty manageable, Charmander outspends and unless you throw Timburr it can't really deal that much damage
Berry juice Ponyta is probably the easier matchup of the 2 sets but it still walls charmander while threatening high horsepower. You can use your evio Ponyta to kill it with high horsepower while tanking theirs.
236 Atk Ponyta High Horsepower vs. 0 HP / 0 Def Eviolite Ponyta: 14-18 (66.6 - 85.7%) -- guaranteed 2HKO
236 Atk Ponyta High Horsepower vs. 36 HP / 0 Def Ponyta: 22-26 (100 - 118.1%) -- guaranteed OHKO
Sash Diglett kills it even with flame charge as long as you get a free switch.
Eviolite Ponyta is harder to counter, you don't have the same high horsepower advantage so it becomes a speed tie and Diglettt can't ohko it. However it's pretty uncommon for evio Ponyta to run high horsepower and if they don't you can kill it with your own.
I hate Tyrunt. I have one really specific tactic to deal with this mon but it requires sash to be up on Diglett, Timburr to be alive and not burned and to sacrifice 1 mon for a little chip dmg and a free switch. Timburr and Diglett can deal dmg with priority moves to take care of Tyrunt.
156 Atk Diglett Sucker Punch vs. 0 HP / 0 Def Eviolite Tyrunt: 4-5 (18.1 - 22.7%) -- possible 5HKO
196+ Atk Iron Fist Timburr Mach Punch vs. 0 HP / 0 Def Eviolite Tyrunt: 12-14 (54.5 - 63.6%) -- guaranteed 2HKO
But for this to work you need 6hp of chip. This isn't really a problem. Every mon on the team can deal 6hp most of the time (6hp is 27%)
0 Atk Larvesta U-turn vs. 0 HP / 0 Def Eviolite Tyrunt: 7-9 (31.8 - 40.9%) -- 17.6% chance to 3HKO
196 SpA Vulpix Energy Ball vs. 0 HP / 76 SpD Eviolite Tyrunt: 5-7 (22.7 - 31.8%) -- 99.9% chance to 4HKO (Possible damage amounts: (5, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6, 7) so you would be really unlucky do low roll on energy ball, sucker and mach)
196 SpA Solar Power Charmander Weather Ball (100 BP Fire) vs. 0 HP / 76 SpD Eviolite Tyrunt in Sun: 4-6 (18.1 - 27.2%) -- 1.4% chance to 4HKO (since you outspend after 1 dd you can weather ball twice for the dmg).
This is a really consistent counter but it requires a lot of resources. If your opponent doesn't have any other hard counters its usually an ok trade
Rocks are horrible for this team and Dwebble is one of the best rockers in the tier. you can beat Dwebble and keep rocks off with but it leaves your Timburr low so make sure you only use this Strat if you don't need hp on Timburr. Swap Timburr in on rocks, defog on knockoff.
156 Atk Dwebble Knock Off (97.5 BP) vs. 0 HP / 156 Def Eviolite Timburr: 2-3 (8.3 - 12.5%) -- possible 8HKO
Knock off on rocks
196+ Atk Timburr Knock Off (97.5 BP) vs. 0 HP / 116 Def Eviolite Dwebble: 5-7 (23.8 - 33.3%) -- 0% chance to 3HKO
Defog again on rock blast
156 Atk Dwebble Rock Blast (3 hits) vs. 0 HP / 156 Def Timburr: 6-9 (25 - 37.5%) -- approx. 1.1% chance to 3HKO
Mach punch on rocks (you don't want to kill it with drain because your opponent could deny defog with the free switch
196+ Atk Iron Fist Timburr Mach Punch vs. -1 0 HP / 116 Def Dwebble: 9-12 (42.8 - 57.1%) -- 12.1% chance to 2HKO
Then you can defog on rock blast again and knock it out with mach punch. This leaves your Timburr knocked off and around 30% so it could still be useful for Carvhana Pawniard or Tyrunt but other than that its out of the game. If you need Timburr to wall something like Frillish you can lead Diglett into Dwebble, abuse Weak Armor with beat up to lower its defence to 0 and sucker to knock it out. Then you can either switch to Diglett and defog since its at full health or final gambit and go Timburr depending on your opponents switch.
Shell smash Dwebble gets walled by Timburr as long as you have 60% hp.
+2 236+ Atk Dwebble Earthquake vs. 0 HP / 156 Def Eviolite Timburr: 11-14 (45.8 - 58.3%) -- 94.1% chance to 2HKO
196+ Atk Timburr Knock Off (97.5 BP) vs. -1 0 HP / 0 Def Dwebble: 12-15 (57.1 - 71.4%) -- guaranteed 2HKO
196+ Atk Iron Fist Timburr Mach Punch vs. -1 0 HP / 0 Def Dwebble: 9-12 (42.8 - 57.1%) -- 12.1% chance to 2HKO
If you don't have Timburr healthy though you get swept if you let it set up.
Mudbray is hard to deal with since it runs scarf or rocks. You can't really switch Timburr into Mudbray like you can with Dwebble. Luckily you can ohko it with Charmander.
196 SpA Solar Power Charmander Weather Ball (100 BP Fire) vs. 0 HP / 0 SpD Eviolite Dwebble in Sun: 24-28 (114.2 - 133.3%) -- guaranteed OHKO
Same thing goes for scarf, but if you manage to knock its scarf of you can beat it with Ponyta too.
Onix is a lot like Dwebble, it gets walled by Timburr but if you lose Timburr you're fucked. Usually this set leads to set rocks but you can take care of that with defog -> knock -> defog - >mach -> defog -> mach or knock -> drain if they can't deny defog with something like Abra.
196+ Atk Timburr Knock Off (97.5 BP) vs. 76 HP / 0 Def Onix: 6-8 (28.5 - 38%) -- 59.1% chance to 3HKO
196+ Atk Iron Fist Timburr Mach Punch vs. 76 HP / 0 Def Onix: 12-14 (57.1 - 66.6%) -- guaranteed 2HKO
196+ Atk Iron Fist Timburr Drain Punch vs. 76 HP / 0 Def Onix: 14-20 (66.6 - 95.2%) -- guaranteed 2HKO
If you realise its not sturdy-juice you can ohko it with solar blade.
236 Atk Ponyta Solar Blade vs. 0 HP / 0 Def Eviolite Onix: 20-28 (100 - 140%) -- guaranteed OHKO
Sturdy-juice can actually only switch into weather ball once and other sets can't switch in at all unless you lowball.
196 SpA Solar Power Charmander Weather Ball (100 BP Fire) vs. 76 HP / 0 SpD Onix in Sun: 16-20 (76.1 - 95.2%) -- guaranteed 2HKO
196 SpA Solar Power Charmander Weather Ball (100 BP Fire) vs. 0 HP / 76 SpD Eviolite Onix in Sun: 9-12 (45 - 60%) -- 82.4% chance to 2HKO
Archen's scarf set is extremely scary since it speed ties with Charmander. It's really manageable if you get it below deafest range.
180 Atk Defeatist Archen Earthquake vs. 44 HP / 12 Def Charmander: 14-18 (66.6 - 85.7%) -- guaranteed 2HKO
It kills your entire team with either dual wingbeat or earthquake except Larvesta and Ponyta the former can't really touch Archen.
180 Atk Archen Dual Wingbeat (2 hits) vs. 76 HP / 236+ Def Eviolite Larvesta: 16-24 (69.5 - 104.3%) -- approx. 6.3% chance to OHKO
180 Atk Archen Earthquake vs. 0 HP / 0 Def Eviolite Ponyta: 16-20 (76.1 - 95.2%) -- guaranteed 2HKO
So you have 4 mons that can hit it to get it below 50%, u-turn/flare blitz Larvesta, mach punch Timburr, sucker Diglett or Ponyta.
196+ Atk Iron Fist Timburr Mach Punch vs. 76 HP / 0 Def Archen: 9-12 (39.1 - 52.1%) -- 0.4% chance to 2HKO
0 Atk Larvesta Flare Blitz vs. 76 HP / 0 Def Archen: 9-11 (39.1 - 47.8%) -- guaranteed 3HKO
0 Atk Larvesta U-turn vs. 76 HP / 0 Def Archen: 5-6 (21.7 - 26%) -- 73.8% chance to 4HKO
156 Atk Diglett Sucker Punch vs. 76 HP / 0 Def Archen: 7-9 (30.4 - 39.1%) -- 85.5% chance to 3HKO
236 Atk Ponyta Solar Blade vs. 76 HP / 0 Def Archen: 15-18 (65.2 - 78.2%) -- guaranteed 2HKO
236 Atk Ponyta Flare Blitz vs. 76 HP / 0 Def Archen: 10-12 (43.4 - 52.1%) -- 42.2% chance to 2HKO
236 Atk Ponyta Flame Charge vs. 76 HP / 0 Def Archen: 4-6 (17.3 - 26%) -- 0.1% chance to 4HKO
Your best option is probably flame charge+solar blade/flare blitz if sun is not up but anything that brings it below 50 works.
Berry juice Archen is a lot less threatening, any amount of chip gets it in range of Charmander overheat.
196 SpA Solar Power Charmander Overheat vs. 0 HP / 76 SpD Archen in Sun: 19-23 (86.3 - 104.5%) -- 25% chance to OHKO
Scarf gets destroyed by any fire attack, get outside by Charmander and Diglett ohko's it as long as mag doesn't flash cannon on a switch.
Sturdy juice is really annoying since it can stall sun turns easily but if you get a u-turn on it its dead to Diglett. also flame charge Ponyta can pp stall recycle or force it out.
Munchlax is scary but as long as you don't let it set up to +2 you can kill it with Timburr. Swap after curse 1, drain on curse 2 to proc berry juice. drain on curse 3 to get it to 12hp and then you knock it out with drain before curse 4 can go off. Munchlax doesn't get any breathing room for recycles. at its best it can stall you 16 drain punch pp but if you crit once its over which with the highball of the first drain punch is around 70% (im not a statistic genius so this might be wrong).
196+ Atk Iron Fist Timburr Drain Punch vs. +1 0 HP / 36 Def Munchlax: 24-30 (80 - 100%) -- 6.3% chance to OHKO
196+ Atk Iron Fist Timburr Drain Punch vs. +2 0 HP / 36 Def Munchlax: 14-20 (46.6 - 66.6%) -- 99.6% chance to 2HKO
196+ Atk Iron Fist Timburr Drain Punch vs. +3 0 HP / 36 Def Munchlax: 14-18 (46.6 - 60%) -- 12.1% chance to 2HKO
I don't really know how hard Shellos is to deal with since its a crit-me-not sweeper and im not dealing with the statistics of crits and I can't remember the last time I fought a Shellos. you could probably do something with final gambit Diglett and solar power Ponyta but you risk the recover on the final gambit.