I was playing pvp when this happened

You can see in the battle tab, that even after Charizard's mega the swampert hit first, that doesn't make sense because the sun is already on the field and he didn't put any effect with tailwind just hit first, obs = this zard has 317 spd

Hello @Kaio543,

 

Thank you for taking the time to make this report. This behavior may seem weird but is actually intended and hasn't changed since Generation VI. In general, the outcome is determined by the weather that is active at the start of the turn, as well as the Mega Evolution order and the initial ability of each Pokemon.
 

For example, if Rain is active at the start of the turn, Mega Swampert will still go first even if Charizard Mega evolves into Mega Charizard Y and sets up Sun. However, if Rain is active at the start of the turn and Swampert is also not Mega evolved, Charizard will Mega evolve, set up Sun, and outspeed it even if it Mega evolves as well. Both examples assume optimal Speeds for Swampert and Charizard. In the first case, Mega Swampert's ability is Swift Swim; in the second case, Swampert's ability is either Torrent or Damp, meaning that the active weather at the start of the turn won't affect its Speed.

 

If you wish to report something else, please feel free to create a new thread in the Bug Resolution Center. Thank you and have a good day!

 

Regards,
Unowned