Note : If he mentions heavy rain, that refers to Kyogre. You can either catch Kyogre first or wait for the weather to reset.
: You must move fast. If you take too long, the weather pattern will shift, the cave will disappear, and you’ll have to check back with the scientist for a new location. Battle Details & Stats Find Groudon Pokemon Emerald
: Groudon will appear on one of four possible routes: 114, 115, 116, or 118 . Note : If he mentions heavy rain, that refers to Kyogre
Once inside Terra Cave, you will find Groudon at the end of the tunnel. the weather pattern will shift