Fingers of Frost is a passive mage ability learned at level 24 for those with the Frost specialization. When triggered, it grants the mage a buff that makes their next [Ice Lance] or [Deep Freeze] treat the target as if it were Frozen, but not really freezing it, and also increases the damage of Ice Lance for a short amount of time.
This ability shines when used in conjunction with [Shatter], causing the spells to be cast under its influence to have a high chance to critically strike.
In PvP, channeling two Frostbolts and then immediately following with a Deep Freeze can be a devastating combo, since the Deep Freeze allows another two-three spells (depending on spell haste) to hit the already weakened target.
Patch 6.0.2 (14-October-2014): Fingers of Frost now increases Ice Lance damage by 100% (up from 25%).
Patch 5.2.0 (5-Mar-2013): Fingers of Frost now has a 15% (was 12%) chance to activate from Frostbolt, Frostfire Bolt and Frozen Orb, and a 5% (was 4%) chance to activate from Blizzard.
Patch 4.1.0 (26-Apr-2011): Fingers of Frost bonus damage applied to Ice Lance has been increased to 25%, up from 15%.
Patch 4.0.6 (8-Feb-2011): Fingers of Frost can no longer be dispelled and now also increases Ice Lance damage by 15%.
Patch 4.0.3a (2010-11-23): Fingers of Frost proc chance is now 7/14/20%, down from 10/20/30%.
Patch 3.3.3 (2010-03-23): Mages with Molten Armor active who have the Shatter talent will no longer lose Fingers of Frost charges when Molten Armor causes reactive damage. In addition, the effect from this ralent now displays the number of charges on the buff icon.
Patch 3.3.0 (08-Dec-2009): This talent now triggers immediately on casting a spell rather than being delayed until the spell strikes the target.
Patch 3.0.8 (2009-01-20): This talent can now trigger properly from Frost Armor.