Omen of clear sky

[Rodrigo]

Quick question, using this omen you don't need the seer to reduce the mist distance? does this perk already pushes it back all on its own?

[Muscarine]

You can still push it back further, but frankly it's not needed

[Bumc]

Only thing it does is stopping the mist 2 tiles farther than normal "they are right up in your face" level.
You probably don't want to use it unless you're doing some kind of challenge run.