While most Pokémon won't evolve until they reach a certain level or require items, there are several Pokémon that simply need time to evolve. In order for a Pokémon that evolves after a certain amount of time to evolve, the Time Counter must be two hundred twenty or greater. Pokémon that are caught in the wild, for the most part, begin with a Time Counter of seventy. This number increased by two every sixty-four hours if it is less than two hundred and by one if it is two hundred or higher. In addition, when Pokémon that evolve after a certain amount of time has passed increase in Level, the Time Counter increases as well. If the counter is less than one hundred, the Time Counter will increase by five. However, if the counter is one hundred or greater, but less than two hundred, the counter will increase by four. Lastly, if the counter is already two hundred or greater, it will increase by three if a Pokémon gains a level.
It is important to note, however, that simply reaching two hundred twenty on the Time Counter is not enough. Once the Time Counter has reached that number, the Pokémon must gain a level and, for a few of them, it must be during a specific time of day.
The following Pokémon evolve using this method:
Golbat -> Crobat
Chansey -> Blissey
Eevee (Day) -> Espeon
Eevee (Night) -> Umbreon
Pichu -> Pikachu
Cleffa -> Clefairy
Igglybuff -> Jigglypuff
Togepi -> Togetic
Azurill -> Marill
Budew (Day) -> Roselia
Buneary -> Lopunny
Chingling (Night) -> Chimecho
Munchlax -> Snorlax
Riolu (Day) -> Lucario
Woobat -> Swoobat
Swadloon -> Leavanny
If a Time Counter is at seventy and Pokémon do not gain levels, it will take four thousand, one hundred sixty hours to reach two hundred and an additional one thousand, two hundred eighty hours to reach two hundred twenty, meaning it will take approximately two hundred twenty-six days and sixteen hours to evolve.
In addition, there is an item known as the Soothe Bell that doubles the levels on a Time Counter, so instead of two points, the counter would get four, and so on.