You have learned to enter a deeper state when casting spells, allowing you to shrug off distractions, damage, weather effects, and even the effects of other spells.
Prerequisites: Combat Casting.
Pathfinder Roleplaying Game: Ultimate Magic. © 2011, Paizo Publishing, LLC; Authors: Jason Bulmahn, Tim Hitchcock, Colin McComb, Rob McCreary, Jason Nelson, Stephen Radney-MacFarland, Sean K Reynolds, Owen K.C. Stephens, and Russ Taylor.