Yes, after beating Elite 4, talk to the leader prof. in the Weather Institute. If he tells you that he observed a Drought in route <insert route number here>, go there, and if sun will be just melting (it will be white flashing in this route), look for the cave. If you enter, it's only 2 small floors, and in the 2nd floor is Groudon. If that guy tells you, that, there were a heavy Rainfall in route <insert route number here, only water routes>, go there, and when you discover an unknown diving spot near a large rocky formation (the diving spot must be very small, and it's raining in this route), dive here. On the 2nd floor, like with Groudon, there will be Kyogre. But if finding da caves takes you too much time, they disappear, and you must talk to the leader prof. in Weather Institute again. <<< A big guide written by me.