If you’re in the market for rare art, seeing Redd’s rickety-looking boat docked on the far shore of your island is probably a welcome sight. You’ve waited all week, and now you can finally overpay for a faux Rembrandt that Blathers won’t display in the museum.

Like every Animal Crossing title, New Horizons’ NPCs are a huge part of the game. But the seemingly random schedule by which vendors and other NPCs appear is irksome to players who wish to chart out their gameplay or plot their next purchase. If you’re in need of large star fragments, knowing just how long you’ll be waiting for Celeste can be useful.

Thanks to data miner, Ninji, the top-secret mechanisms that control NPC behavior in New Horizons are not so secret anymore. An incredible source of ACNH reveals over the last few weeks, Ninji is quickly amassing a sizable following. “Not Animal Crossing Tech Support,” his Twitter bio qualifies. Late last week, one post, in particular, won the attention of the ACNH community. “Here’s the tea on #ACNH NPC spawns,” he shares.

The basics are relatively simple. Once the Able Sisters set up shop, players are guaranteed weekly visits on a random weekday from Sahara, Kicks, and Leif. This leaves the other two remaining weekdays left to be filled at random by either Gulliver, Label, CJ, Flick, or Redd, says Ninji.

Celeste and Wisp operate on separate schedules, unimpacted by the behavior of the other NPCs. On days that demonstrate meteor shower weather patterns (clear skies), Celeste will appear. If you have more than one day with clear weather in a week, Celeste picks one at random. Wisp just shows up on a random day, so there’s really not much you can do to plan for the spirit character’s arrival (not that you really need to anyway).

There are clearly RNG mechanics built into NPC behavior, the data mine finds, but NPCs that fail to show up one week will be given priority the following week “as a form of bad-luck prevention.”

The Official Guide to ACNH informs players that Sahara and a few other NPCs do have the ability to appear on weekends, but this information is not evident in the code, according to Ninji.

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