Originally Posted by Fat Kaphotics
IVs are generated RIGHT as the rain lets lets up. The rain lets up a few seconds after the roamer flies off the screen. So IV's are definitely easy to reset for, but nature and shiny (when we get there) will be nigh impossible at this location on a cart, unless you are extremely extremely extremely persistent (and lucky). It's still an absolute crapshoot because of the rain.
What we need to do is figure out the rate at which the rain advances the PIDRNG, so it's feasible for someone using non-C-Gear seeds and a timer. The only problem is we don't have a way to verify the seed, so you'd have to track down the roamer and catch it to check.
There's a guy who gives you a random fossil once a day, maybe that could be used to check. Assuming there are no other NPCs between the roamer and flying off to the fossil guy.