In addition to the primary effect of lowering Evasion, Defog also has a number of other secondary effects.
When used outside of battle in Diamond, Pearl, and Platinum, Defog clears away heavy fog. These are the only three games in which this effect is utilized outside of battle. In battle, Defog is also used to clear away heavy fog during the aforementioned games and Pokémon Battle Revolution.
Pokémon that Learn this Move via Level-Up
Pokémon that Learn this Move via Breeding
Pokémon that Learn this Move via Sketch
Related ThreadsDefog isn't useful? - last post by @ Aug 14, 2010
how do you get defog - last post by @ Sep 25, 2007
Never given Defog, only shards at the Great Marsh - last post by @ Jul 18, 2016
defog - last post by @ Aug 15, 2009
defog - last post by @ Jul 25, 2009