In comparison to the other Pokemon leagues -
For the Indigo league it was 'exactly two months from today' in Showdown at the Poke-Corral, and the league started 9 episodes later in 'Round One - Begin'
For the Johto league it was 'three months from now' in 'Why Why Not', the league started 11 episodes later in 'A Claim To Flame'
For the Hoenn league they mentioned it was three months away in 'Eight Ain't Enough', followed by the league starting 15 episodes later in 'Saved By The Beldum'
For the Sinnoh league it was taking place in 'a month' from 'The Eighth Wonder of the Sinnoh World', and the league started 4 episodes later in 'League Unleashed'
So they have been broadly corresponding to actual time in the past, though not exactly, and obviously if there were double episodes or breaks in the airing it would be different.
I really hope they don't try and squeeze the World Tournament before the League, and that instead we just get some training episodes and filler. I want to be able to find Ash's success or lack thereof to be believable. While Ash should be able to beat all his current rivals, that would just mean Ash being successful at the least challenging league, rather than actually deserving a win based on steady improvement (he should finish second based on the overall progression). I do think he's shown signs of improvement in recent battles, but he hasn't done anywhere near enough training, and hasn't even had a full battle at any point in the series.
If the World Tournament is first and he loses it, there's not enough time to justify turning things around for a win at the league.