Drought creates harsh sunlight when the ability-bearer enters battle. The effect lasts 5 turns, unless it is cleared via Air Lock or Cloud Nine, or replaced by another weather condition.
If multiple Pokémon with weather-generating abilities (Drought, Drizzle, Sand Stream, or Snow Warning) enter the field on the same turn, each weather condition will activate consecutively, with the fastest Pokémon first. Thus, the resultant weather condition will be that of the slowest Pokémon.
Prior to Generation 6, Drought lasts indefinitely upon activation.