Defog can now be reflected with Magic Coat and no longer lowers the evasion of a Pokémon behind a substitute.
Generation VI onward
Defog now clears away Spikes, Toxic Spikes, Stealth Rock, and Sticky Web on both the user's and target's side of the field as well as Aurora Veil on the target's side of the field. It still only clears away Light Screen, Reflect, Safeguard, and Mist from the target's side of the field.
If powered up by a Flyinium Z into Z-Defog, the user's accuracy is raised by one stage.
Starting in Generation VIII, Defog now clears Terrains.
Outside of battle
Defog clears away fog from the area. The effect lasts until the player leaves the area.
Honchkrow's wings become outlined in a light-blue glow. The outline disappears as it releases multiple light-blue crescents by flapping its wings. Its wings then become outlined again as the crescents go for the opponent.
The Bag sprite for the HM containing Defog is mistakenly that of a Water-type HM, rather than a Flying-type one.
Like Flash was in Generations I, II, and III, Defog is not critical to the completion of the game, as a player can traverse foggy areas without using the move. However, unlike with dark caves requiring Flash to light them, foggy areas affect battles within them.
If a player teaches a Pokémon Defog by HM in Diamond, Pearl, and Platinum and trades it to HeartGold or SoulSilver, the Pokémon can be freely imported to Black and White via the Poké Transfer, due to Defog not being needed outside of battle in HeartGold and SoulSilver. The same can be done with Whirlpool by transferring a Pokémon that learned it by HM in HeartGold or SoulSilver to Diamond, Pearl, or Platinum.