Battling rules question

[kavemank]

I have tried to find the answer to this everywhere but have had no luck, a friend of mine were trying to figure this out and each came to different conclusions so any help would be appreciated. If you and your opponent both send in a Pokemon to battle at the same time and they both have a weather ability, which ability stays and which one goes, and why?

 

[faucin]

i think the ability activation turns are based in the pokemon speeds, so the faster pokemon activates the weather first and then the other one, so the slower pokemon wins the weather. still im not 100% sure

 

[UB-01 Kenobi]

i think the ability activation turns are based in the pokemon speeds, so the faster pokemon activates the weather first and then the other one, so the slower pokemon wins the weather. still im not 100% sure

That is correct.