Do you want to know what the Stalk Market turnip prices are going to be on your island?

They follow rules very similar to the turnip prices in AC:NL.

Each week, you can get one of four preset price patterns for the week.

The first week you buy turnips on your own island, you are guaranteed a gentle BUMP pattern. Turnips will sell for 40% to 90% their base price, then decrease 3% to 5% each half day. Some time between Tuesday AM and Thursday PM, prices will be increased for five half-days.

For two half-days, you'll see prices between 90%-140%. Then for three half-days, you'll see prices between 140% and 200%, with the highest price always occurring on the fourth half-day. After the 5-period boost, prices will snap back to 40% to 90%, then decrease 3%-5% each time.

The DECAY pattern starts at 85% to 90% your purchase price, then decreases 3% to 5% each half-day. It's impossible to make a profit during this week, but you can't be certain you have it until Thursday PM. Make friends!

The SPIKE pattern also starts at 85% to 90% your purchase price, then decreases 3% to 5% each half-day. Between Tuesday *PM* and Thursday PM, a five price pattern will start. The highest price will be on that third half-day.

SPIKE prices, in order, will be 90-140%, 140%-200%, 200%-600%, then back down: 140-200%, 90-140%. Afterward, prices will randomly hover between 40% to 90%.

The last pattern, TRIPLE, is the most complicated, but it features five days of low prices (80% or less) and seven days of OK prices (90% to 140%). This pattern features a high-low-high-low-high pattern for the week.

TRIPLE's first and last high phases might not happen at all, but you still always get 7 high days total. the middle high phase always lasts for at least one price. These prices will be 90%-140%.

TRIPLE's low phases are always 2-3 days each and total 5 days. Prices will snap back to 60% to 80% and then fall an additional 4% to 10% a pricing period.

Lastly, concerning base prices: the base price is your purchase price. EXCEPT the first week you buy on your own island, in which case the base price isn't known(!) and is somewhere between 90 to 110 bells.

.... And that's all! Thanks to @_Ninji for their analysis and RE work uncovering the governing mechanisms. I just transcribed from code to tweets .

Whoops, I made an error in this thread. Spikes can start as early as Monday PM. Bumps can start as early as Monday AM.

I keep forgetting when the AC week starts