In Pokémon Sword and Shield, there's an array of Pokémon you can capture without considering anything else. Yet the Pokémon available, depending on if you're in the Wild Area or not, differs due to certain mechanics. Two main features change what Pokémon appear in each area of the game; the two key features are time and weather. These must be taken into account if you are trying to catch 'em all, as some Pokémon only appear at night or in certain weather conditions. No matter what timezone you are from, it'll always turn night in the game when it starts to get dark for you. This is not the same for how the weather works, as the weather is based on key dates.
Knowing what weather will be active on certain dates in the Crown Tundra is essential when trying to capture particular Pokémon. Pokémon Sword and Shield's weather is not random; certain dates cause specific weather to occur. There are 9 different kinds of weather, and it's handy to know which one you want to befall.
Because the weather is not random, there is no way to manipulate it apart from changing the date of your Nintendo Switch, and this must be done from your Nintendo Switch settings; it cannot be done in-game.
The dates are different from Pokémon Sword and Shield's base game and the first DLC Isle of Armor. You can do these at any point in the story (dates are in US format):
- Snowstorm: 1/31/2020
- Cloudy: 3/31/2020
- Clear: 4/31/2020
- Intense Sun: 5/31/2020
- Snow: 6/30/2020
- Fog: 7/31/2020
- Sandstorm: Sandstorm does not appear in the Crown Tundra
- Rain: Rain does not occur in the snowy areas of the Crown Tundra.
- Thunderstorm: Thunderstorm does not occur in the snowy areas of the Crown Tundra.
How to change your date
To change the date on your Nintendo Switch, make sure that everything is closed down, that you have no games running. Then go to System Settings>System>Date and Time. First, you need to uncheck the Synchronize the Clock via the Internet, as this will stop your date from defaulting back to the real one. Next, go to the Date and Time and set it to the desired date above to get the weather you want.
Once you've set the date, go ahead and reopen the game, do not connect to the internet via Y-Comm. If you did it correctly, all of the Wild Areas weather will be set your desired weather!