First make sure the cowl drain holes are not blocked with leaves or debris,and drain properly. It there are leaves in the cowl you will have to get them out from the interior vents,or try to spray them out with a hose.
Wipers as stated are a very common source for a leak.
The windshield can also leak in the bottom corners. Water getting past the weatherstrip.
Both my cars are garaged,but i had one outside.If I knew a storm was coming in, I would use blue (painters) tape,and tape problem ares.
and use a car cover. When the storm passes,peel the tape off a look for wet areas. Get out a towel and dry it up. Roll down the windows and open trunk also helps to dry it out.