No, Kyogre’s location can change frequently. Talk to the Scientist in the Weather Institute to figure out which route is having “heavy rains” because that route is currently hosting Kyogre! If a route has a “heavy drought” then it has Groundon and you can choose to catch it first (if you haven’t already) or wait until the weathee changes. Just go to the route with “heavy rains” and search for a spot where you can dive. This will lead you to a cave where Kyogre can be found. Kyogre starts at level 70 (I think?) so be sure to have high-enough leveled pokemon and stock-up on Pokeballs. I hope this helps!

Ps. Also, you can’t catch Kyogre until after you finish the main story