Goudon&Kyoger

Go back 2 the place where you got castform (sorry I can't rember the route, but it's jus a lil bit b4 foretree) go talk 2 the guy you saved and he will tell you there are wierd wheather patterns on a route. If it's heat waves then it's groudon and if it's heavy rain then it's kyoger. (o don't worry you get both so after the first one go back and he will tell you the next one) hope I helped.

So fly to fortree, and go to the route before it. Go to the weather institute and talk to the guy at the far end of the upstairs floor. He will first tell you that there is a heavy downpour on a certain route. You need to go to that route an have a Pokemon that knows surf and dive in your party. Now find a spot where you can use dive. Dive down and go along the path for a little while. If you see a cave, go in and surface. Now go until you see a pool with kyogre in it. DO NOT GO UP TO THE EDGE OF THE POOL UNLESS YOU HAVE SAVED. Once you are at the edge, the Pokemon will come over, and you'll face a lv. 70 kyogre with the drizzle ability (makes it rain for the duration of the battle), and sheer cold, which will one hit ko you if it hits, hydro pump, rest, and double edge. Now repeat the process for groudon. Got to the weather place, talk to the guy find out what route the drought is on, go there, find a cave, go in, groudon's in a pit of lava, don't go you to the edge unless you are ready to fight it, it has drought ability, the whole battl wil be in bright sunshine, it has fire blast, rest, solarbeam, and fissure(one hit ko if it hits). They both have decent catch rates, just weaken them and use lots and lots of ultra balls. It took me about 15 for kyogre, about 20-30 for groudon. Hope this helps!