Espeon and Umbreon
Let’s just get it out of the way, I’m a scrub..
Does Eevee have to remain your buddy after you walk the 10k in order to evolve it into espeon and umbreon?
And while I got you guys here, does PoGo have designated “night” and “day” times, or is it just based off whether the game displays night or day?
Cause if I waste another 97.5% eevee and it becomes a vaporeon instead of an espeon I’m going to snap my phone 😁
Answers
It must be your buddy at the moment of evolving. Doesn't need to "remain" your buddy, thought. Once you earn 2 candies you can forget about it and set it as buddy later, when you intend to evolve it. This way if you finish walking at night time (in game night) but you want espeon, you can set another buddy to keep getting advantage of your distance. The next day when it's day in game, you must set Eevee as your buddy and finally evolve to espeon. Easy peasy!
More accurately, it needs to be your buddy when you evolve it. After walking the full 10 km and earning 2 candy, you can change to a different buddy if you don't want to evolve right away. For example, if you want to wait for when you are using a lucky egg. I would recommend renaming it with a symbol or something at the beginning of its name to make it easier to find when you are ready to re-buddy it to evolve.
The day/night requirement is based on what is displayed in game. Make sure you are somewhere with good GPS signal, because that is how the game knows where you are. Reportedly if you have a "GPS signal not found error" when you try to evolve, then it defaults back to Jolt/Vap/Flar.