How much does switching out affect the moves' accuracy, and which moves reliably hit Pokemon switching in?

Question

I run Pokemon with moves that have a base accuracy of 100% on opposing Pokemon, and I find that they have a tendency to miss frequently against Pokemon switching in, so I want to know by how much accuracy is reduced against Pokemon switching in, and which moves do not have their accuracy reduced against Pokemon switching in.

Comments

What game/format are you playing? Are you using emulators or simulators like Showdown?

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The actual games

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Which game specifically?

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Scarlet and Violet

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Which move(s) were you using?

Answer 1

Switching Pokemon has never (with one possible exception) affected the accuracy of moves. The list of modifiers can be seen in the table below, up-to-date since Generation V. Note that switching out isn't recorded anywhere.

Accuracy (Bulbapedia)

To my knowledge, only one move's accuracy is affected by switching: Pursuit. Since Generation II, Pursuit doesn't perform accuracy checks if used on a target that's switching out on that turn.

Pursuit (Bulbapedia)

Comments

Ah, I see, so the only thing I can think of now is that I must have had a move with 90% accuracy or so miss something that was switching in.

Answer 2

There are a few possible explanations:
1. The Pokemon switching in has an ability that raises evasion, such as Sand Veil, or was holding an item that lowers accuracy, such as Bright Powder. Amethyst's answer has a complete table of all possible modifiers.
2. Your Pokemon's accuracy was lowered, which may cause 100% accurate moves to miss
3. You mistook a move failing or having no effect for missing. For example, using Spore on a burnt opponent or using Sucker Punch against a Pokemon switching in would fail, while using a psychic-type move on a disguised Zoroark would show up as having no effect.
4. You were in a double battle and targeted the wrong spot.
5. You were in a double battle and the move was redirected via a move like Rage Powder or Follow Me.
6. You mistook 100 Power for 100 Accuracy.

If you want a better answer, please tell us what move you were using and against whom.