Front/side winds are up there, too. Combine that with water on the roads, and it's horrible!Rain and especially standing water is the single worst thing for efficiency. You can’t compare wet vs. dry at all. Wait till it stops raining and the efficiency gains will be apparent.
Driving on the freeway yesterday from NorCal to SoCal and efficiency was 350 Wh/mi at the best and at times over 400 Wh/mi (granted, this was on CrossClimate 2s, not iON EVO AS).