Kat West "Pokémon Go Weather effects system benefits and boosts explained to help you get Cacnea and Lotad"

https://www.eurogamer.net/articles/2018-02-23-pokemon-go-weather-effects-cacnea-lotad-4819

Pokémon Go Weather effects add something new to consider when going out to look for Pokémon in the wild.

Whether it's raining, sunny or just plain cloudy, different Pokémon will appear based on your local weather, and give boosts to certain Types related to how it's looking outside - so expect Fire Types to be that little bit stronger when the sun is out.

Released alongside the December 2017 Gen 3 update, though we don't know the full extent of how weather changes every spawn, we have a good idea of the many benefits it will bring.

What are Pokémon Go Weather effects?

For the first time in the game, as well as your geographical surroundings (such as bodies of water) affecting the types of creatures that spawn, the local weather will change what creatures you see and how they behave.

Weather effects will impact the game in four ways:

• New visual effects
• Seeing different Pokémon Types spawn
• Increasing the level (CP) of spawning creatures both in the wild and in Raids
• Certain Types will be more effective in battle (by around 20%)
• Increases to Stardust when catching certain Types by 25 percent

There are numerous weather effects. First indications show that it does make certain creatures become far more common - or rarer - and though there doesn't appear to be any weather exclusive spawns, long term it could have interesting dynamics on the game's meta based on creatures that are more popular based on climate, through to how powerful they are during certain seasons.