Interestingly your tyre choices are deemed ok for Wet Grip / all season. What sort of mileage have you done on them? Is it hydroplaning or general lack of wet grip you are suffering from? Hydroplaning is where the tyre is separated from the road surface due to excessive water on the road surface, lack of wet grip can be down to harder compounds, new tyres still having releasing agent on them from manufacturing or even poor wheel alignment. Are you liberal with the polish on your car - could the tyres have picked up waxes from polishing? Out of interest how does your ESP cope with it?