How to get a Meteorite for Mega Rayquaza in Pokémon Go
To get Mega Rayquaza, you must first teach Dragon Ascent using a Meteorite. Here’s how to get Meteorites in Pokémon Go.
This article references relevant content from the polygon.com website. Original article link: [https://www.polygon.com/pokemon-go-guide/23844046/meteorite-mega-rayquaza-dragon-ascent]

Mega Rayquaza was first introduced to Pokémon Go as part of the Go Fest event in the summer of 2023, following the arrival of Primal Reversion for fellow Gen 3 Legendaries Kyogre and Groudon earlier in the year.
Initially exclusive to attendees at the London, Kyoto and New York Go Fest weekends before rolling out to players globally on Aug. 26, 2023, Rayquaza’s Mega Evolution has a twist — where it must learn a specific move first (Dragon Ascent) through the use of a unique item.
As with all Mega Evolutions, this is a temporary transformation, and still requires collecting Mega Energy from raids and other sources. It’ll also give you party a boost while active — making them useful for Community Day and other events.
How to teach Dragon Ascent to Rayquaza in Pokémon Go
To Mega Evolve Rayquaza, you not only need enough Mega Energy, but the Pokémon also needs to learn a specific move — Dragon Ascent.
Teaching Dragon Ascent to Rayquaza requires the Meteorite item. When used, this will replace a Charged move; if you have just one move available, it’ll simply replace that, otherwise it’s worth unlocking a second Charged move so you have options in battle.

Like Evolution items, Meteorites are consumed upon use, and since they are rare, you have to think carefully about which Rayquaza you spent it on. Our suggestion — a shiny and / or one with strong stats!
How to get Meteorites in Pokémon Go
Meteorites first rolled out following during Go Fest 2023, and can currently be acquired in several ways:
Previous methods include:

After that, the availability of Meteorite is uncertain, but based on Niantic’s track record of previous unique forms and evolution rollouts, it’ll return as part of future Special Research or when Mega Rayquaza reappears in raids.
Meteorities won’t be missable, then, they’re just rare — and you could be waiting a while for the next chance if you don’t play on Aug. 27.
Mega Rayquaza bonuses
As with other Mega Evolutions, Mega Rayquaza not only sees a boost to CP and power for the next eight hours, but also grants additional perks. These are:
You can boost these the more you Mega Evolve, with improvements across three stages: Base Level, High Level, and Max Level.
What else do we know about Meteorities, Dragon Ascent, and Mega Rayquaza in Pokémon Go?
Though Mega Rayquaza is technically just another Mega Evolution, there are some observations and differences to be aware of: