Level 27
It evolves into Jumpluff at level 27 or higher.
Skiploom evolves at level 27.
Skiploom, the grass and flying type Pokemon, evolves to Jumpluff at level 27. Skiploom can evolve from Hoppip at level 18.
Hoppip evolves into Skiploom at Level 18.
hoppip (level 18) skiploom (level 27) jumpluff
Hoppip evolves into Skiploom starting at level 18. From there Skiploom can evolve at level 27 into Jumpluff which has the same typing as Hoppip.
Rephrase your question = What level does snorlax evolve on Pokemon diamond? =
Hoppip first evolves into Skiploom at level 18. Skiploom can then evolve further into Jumpluff at level 27. Jumpluff does not evolve into anything from then on.
Please clarify your question. What level does evolve in diamond? What Pokemon are you talking about?
Lv. 28
Level 27.
Ponyta evolves at Level 40 in Pokemon diamond.