I don’t know about ona week to week basis, but I definitely see daily changes and environmental limitations.
Like there will be days where I see just a ton of Trikes, and other days where I see basically zero but a ton of some other dino. Or there will be a lot of armored dinos out but no raptors, or whatever.
Also, there’s definitely day/night differences. Like I only ever see Majungasaurus at night or very early morning. After about 6AM they stop spawning for me. I’ve never seen a Tarbo at night.
Similarly, I only ever see Sauropods and Puurasaurs in/near parks, and there are only specific areas I can find Succo’s or Para’s.
So there’s definitely some things to learn about the best places/times/days to find specific dinos.