For the first time since the 19th of October 2017, there has been an announcement for new Pokémon for Pokémon Go. Today, 50 new Pokémon from Generation 3 got added to the game, with more coming in the coming weeks. Pokémon that are included with the release are: Treecko, Mudkip, and Torchic, amongst other unnamed Pokémon. This release is a follow up to the aforementioned Halloween update, in which they released a handful of Generation 3 Pokémon that included Sableye, Banette, and Duskull.
Besides the aforementioned release of new Pokémon, there also will be an update regarding the weather. A new feature that got added is that there is overworld weather in the game. This means that the interface adapts to the current weather, so if it's sunny the sun will shine in the app, while if it rains there will be rain in the app. These two are just two examples, as there are 4 more new weather types in the app. Also the real world weather has an influence on the attacks of the Pokémon.
The official announcement reads that "attacks of certain types will be more effective during some weather conditions, so a Charizard’s Fire Spin will perform better on sunny days, for example".
Last but not least, a feature focused on weather-based chances for finding pokémon got added as well. This feature means that "for example, you’ll find your odds of discovering Mudkip splashing around will greatly improve on rainy days, as certain Pokémon types will be more commonly found during various weather conditions", as the official site writes.