Mage · Frost · tier 4 · from level 25

Shatter

+280 Blizzard

3/3 · level 60 · per cast · against Frozen targets · and 13 more

Shatter 123

Rank 3/3

Increases the critical strike chance of all your spells against Frozen targets by 50%.

Blizzard +280 Arcane Missiles +251 Pyroblast +191 Fireball +130 Blast Wave +118 Frostbolt +114 Fire Blast +109 Flamestrike +102 Arcane Blast +94.6 Frostfire Bolt +83.8 Cone of Cold +82.3 Arcane Explosion +59.6 Scorch +43.5 Frost Nova +18.1

Averages, counting crits and misses, for a level 60 Mage with a typical weapon and no other gear or buffs, against a target your level. Worked out from the game's own data, the same way as the Foresight addon.