I have a chevy impala ss 2008 18000 miles that seems to sway or fishtail bad when...

...the roads are wet any ideas? We dont notice this when the roads are dry but the problem is very noticeable when the roads are wet. Kids are scared !

you probably are going to fast for a wet road, your supposed to go right at the speed limit if not 5 under if its bad enough, you need to learn how to drive in the rain, i highly doubt you need new tires since its only 18,000 miles on it unless you do burnouts and drive it like a corvette around corners

You could try new tires, or you could just slow down if you're sliding all over the road.