Consider spending some points into Polymorph and Geomancy as well for some extra survivability. Picking up some healing and shielding skills, like Restoration and Armour of Frost, will help keep your teammates safe from your status storms.
Pressure Spike provides cheap and useful AoE damage and a way to keep fires under control. Use Rain to get your enemies moist, then use Global Cooling or Electrical Discharge to either freeze them solid or zap them into submission.
The Weather Machine build is specifically designed to keep your opponents struggling to mobilise with lingering ailments, most prominently Frozen and Stunned. Learning how to use status effects is a direct path to success in Divinity 2. Key skills – Rain, Hail Strike/Global Cooling, Electrical Discharge, Pressure Spike,.Main skill categories – Hydrosophist and Aerotheurge.
