How to Increase the Chances of Hatching Pokemon you Want

As far as I am aware, this is still a theory but it deals with the biome weather dependency and biome exclusive trails. For those who aren't sure what a biome is; it is a fairly new term used to describe the different habitats such as forests and tundras. I'm not sure of what biomes are in Pokemon go other than a water and grass biome, mostly because of where I live.

Well, what does any of this have to do with hatching eggs? About a week ago, it was cold damp and rainy for a few days in which I was able to hatch eggs still, though it wasn't my common fire or grass types. It was literally water Pokemon one after the other. It is safe to say however that Water Pokemon do spawn more when it rains because that was practically the only thing spawning. I'm still working on testing this, but I believe it to be true because there is a spot I normally walk to get a good sum of water types. I normally end up with 10-20 within the route, nor included what I get from eggs.

I didn't think much of the Pokemon I got out of eggs I hatched while walking this route, mostly because I thought it was by chance. Well the more I started hatching, the most water Pokemon I got, this was also when it was raining a bit though it was clear at the time I walked. I realized what was happening after hatching several eggs, which most were, of course, water type.

Have any 10km eggs you hope to become one of the one of the few water types you can get from them? Well, I would hold off hatching them until it's either cold damp and rainy unless you live near a water biome spawn. This could greatly increase your chances of getting Dratini's if you are still after that Dragonite (like me). Remember, though you have a (possibly) higher chance of getting water types when conditions are right, doesn't mean A) you will get a water type 100% of the time and B) you will get the Pokemon you long sought for and C) this is still speculation in which I hope to get hard evidence for, before I say rather or not it's legit. 

Though this theory makes sense doesn't mean it is true, that's why it is merely a theory. If you wish to be a part of testing this theory, please don't hesitate to let me know your data.