Both games don't have an internal clock feature like gold and silver version so there is no way to change the time.
Chat with our AI personalities
Yes, there is a time capsule on one island
If you want to trade to ruby or Sapphire you have to fine the ruby and the Sapphire on the seivi islands. If you just want to trade to leafgreen then you can trade at any time.
Qwilfish is caught in firered at five island using a super rod in the water its a little rare so it may take time also a shadow qwilfish is available in Pokemon colosseum.
Pokemon LeafGreen does not have a time system. This makes it impossible to do evolutions that involve time such as evolving Eevee into Espeon or Umbreon.
To obtain Dratini in Pokemon Diamond/Pearl: D: Mount Coronet (2nd time) 4FL (1) (Super Rod) P: Mount Coronet (2nd time) 4FL (1) (Super Rod) -OR- GBA Duel Slot Mainly FireRed or LeafGreen