Wikia

Lunar Shower
Lunar Shower (Passive) Passive When you cast Moonfire or Sunfire, you gain Lunar Shower. Lunar Shower increases the direct damage done by your Moonfire and Sunfire spells by 45%, and reduces the mana cost by 30%. This effect stacks up to 3 times and lasts 3 sec.
Usable by
Class	Druid
Properties
School	Physical
Talents
Specialization	Balance
Level required	82
Related buff
Lunar Shower Direct damage of your Moonfire and Sunfire increased by 45%, and mana cost reduced by 30%. Duration: 3 seconds

Lunar Shower is a passive druid ability learned at level 82 for druids who have chosen the Balance specialization.

Patch changes

Patch 5.0.4 (28 August 2012): Updated.
Patch 4.2.0 (28-Jun-2011): Lunar Shower has been redesigned. When casting Moonfire, the druid gains Lunar Shower. Lunar Shower increases the direct damage done by Moonfire by 15/30/45%, and reduces the mana cost by 10/20/30%. This effect stacks up to 3 times and lasts 3 seconds. While under the effects of Lunar Shower, Moonfire generates 8 Solar Energy, and Sunfire generates 8 Lunar Energy. The amount of Lunar/Solar Energy gained does not change based on the number of points spent in the talent, or stacks of Lunar Shower. Those druids who wish to delay transition in or out of an Eclipse state should now cast the one of their two basic attacks which will not move the Eclipse bar (either Starfire or Wrath).
/ Patch 4.0.1 (12-Oct-2010): Added.