Originally Posted by
saviorofhyrule
I typically noticed that the Frostbolt on my mage will hit and not be Out of Range up to within 5 yards of movement (assuming that Frostbolt range has not been changed).
This means that if I start casting Frostbolt and the mob is moving away, as long as the mob doesn't move more than 5 yards than the max Frostbolt range, the spell will go through and the mob will be hit.
I typically use this to maximize my hits on a mob. I position myself so that the moving mob is moving away from me, Frostbolt, and by the time Frost is Out of Range, I hit a Fireball; it gives me more time and I can typically cast a half or even a full spell more depending on how much the mob moved and if the mob resisted the original Frostbolt.