Weather conditions were first introduced in the second generation of Pokémon games (GSC). Initially the weather was activated in battles through the use of Sunny Day or Rain Dance, which were the only weather conditions at this time. Being that abilities were not introduced until the third generation (RuSaEmFRLG) the Pokémon Tyranitar did not have the Sandstream ability and the Sandstorm condition was not yet introduced. The weather also affected several moves (Moonlight, Morning Sun, Synthesis, Solarbeam and Thunder).
In the third generation weather conditions were vastly expanded upon. Two new conditions were introduced, Hail and Sandstorm. Three Pokémon abilities (Drizzle, Drought and Sandstream) activated conditions upon entrance to the battlefield and two others (Air Lock and Cloud Nine) nullified the effects of weather altogether.
With the fourth generation the only weather type not activated via ability, Hail, got Abomasnow which activates the condition with the ability Snow Warning. A new condition was introduced, Fog, though this condition cannot be summoned by move or ability. New abilities were introduced that take advantage of current conditions as well as hold items which extended non-permanent conditions.
Please use the list provided to navigate to pages documenting the aforementioned weather conditions for all information pertinent to them...