Because Pokémon Legends: Arceus has a dynamic overworld, Pokémon encounters and events can only occur when certain conditions are met. This can mean a wide range of requirements—from finishing missions to progress elements in an area or just needing to be present at a specific time of day.
Various different weather conditions can also cause different Pokémon to spawn and may be key components in getting certain species to evolve while training them. This means you rely on the weather conditions in the game to a certain extent when trying to complete your Pokédex.
Unlike the time of day, you can’t simply go through a menu and choose what weather condition will take hold of an area in Hisui. However, you can manipulate the weather by using the rest feature at a Base Camp.
Once you have entered the area you need a specific weather condition for, head to a tent at one of the Base Camps. Then, pick whatever time of day you prefer or need to be active in for your chosen task.
Each time you wake up, you can check your map to see what the weather condition in the area is, based on the symbol in the top right next to the area’s name. If it isn’t the weather you are looking for, just repeat the process until you get the condition you want.
You can’t get all weather types to appear in certain areas, however. You can’t have a blizzard whipping up in non-snowy zones, for instance.
You’ll use the same method when hunting for a Full Moon, but being able to manipulate the weather can be a helpful bonus, especially when looking for certain Pokémon.