Dark Skies
From Arkham Horror Wiki
Dark Skies is a mythos card. It first appeared in the Dunwich Horror expansion.
Card Information
Mythos Type: Environment (Weather)
Gate Opens: Whateley Farm
Clue Appears At: *Devil's Hopyard
Mythos Ability: Fight checks in Arkham are made at a -1 penalty. Sneak checks in Arkham are made at a +1 bonus. Stalkers move like normal monsters.