Here is a mock of my findings in Traditions
On the map you will see a egg hatching route that allows you to encounter Pokestops and the most common areas where uncommon and rare spawns frequently take place. I’ve listed on the side all the Pokémon I have ran into while doing this study. The Pokeballs on the map are the hot spots for uncommon and rare spawns. It wasn’t worth listing the rares I found in their exact spots because it is totally random. What is worth noting is the Traditions area is a Water, Grass, and Bug area. These type of Pokémon are what commonly take over the area. Once every 3 hours something like a Vulpix or Ponyta will spawn in as a random roll that is not effected by the environment.
Hope this helps!
Credit to: Tom Fox