After it rains there is water on front seat floor mats?

Do you have a sunroof? The most likely cause of this is the sunroof drains are clogged.

However, if you don't or they are not clogged then more then likely your cowl area drains are clogged and when it rains it fills up the openings just under the windshield to the point where they reach a grommet for wiring or something and then it comes in.

The way to confirm and find whatever this is, would be to remove the carpet in the front so and then run water over the windshield until you see where the water is coming in.

Please see the info below on sunroofs and we can go from there.

Thanks