it seems that the weather update will come as a separate update from the release of new Hoenn Pokemon. In an article given to the The Verge, Niantic has shared that although 50+ new Hoenn Pokemon are coming later this week, the weather update will be released towards the end of December.
The following statement was given by Niantic:
[…] So the second part of the update — which Niantic says will start rolling out toward the end of the month — will bring this aspect to Pokémon Go. The real-time weather will change the game in a few ways, outside of the obvious aesthetic differences.
In addition, Niantic has clarified a few misconceptions about the new weather system:
- there are no weather exclusives, but there are Pokemon which prefer a certain type of weather, Lotad given as an example (see quote below)
- all generation spawns will be affected by the new weather system
- the system will be real-time
Lotad quote, given by Matt Slemon, a lead developer on the game.
“We don’t have any pokémon that will only show up in a given weather condition, but there are some pokémon who care a lot about their weather conditions, so you can expect Lotad to show up in really large numbers when it’s raining outside. But if you live in an area where it doesn’t really have that much rain, you might still see a Lotad wandering through your habitat.
Additionally, Slemon explained that the weather system was implemented in order to accompany the Hoenn region theme, which typically deals with weather changes and influence of weather.