Another great anti-weather pokemon is Mamoswine. With its new ability, Thick Fat, it can handle Sun teams too now. EQ wrecks Ninetales and Tyranitar, and Ice Shard / Icicle Crash puts an end to Therians, who are a common sight on Rain teams. Hail isn't safe either, since Mamoswine now gets Superpower, which can OHKO Abomasnow and many other Ice types.
Kingdra seems like a great counter to rain, but it counters sun pretty well too. It has a x4 resistance to fire, and a neutrality to Grass- something only Heatran and Chandelure can top. Frail Chlorphyll sweepers also don't like taking repeated Outrages or Draco Meteors to the face, even if Kingdra's SpA is 'just' 95.
Speaking of Heatran, Heatran can be used to counter Sun and Hail, though it's usage in Sand and Rain is quite limited. With the increased usage of Dugtrio on Sun teams, Heatran no longer has the spunk it used to. However, it's still cemented as a great counter to Sun, especially if they don't have Dugtrio.