During my earlier meeting with Forza Horizon 2 devs Playground Games, they put a heavy emphasis on the racer's new dynamic weather system. Raindrops spatter windshields, turn roads into soggy slicks and reduce visibility. At the time I wasn't able to experience the effect for myself, but after a bit of hands-on time, I've learned one crucial point: Summer showers turn exotic supercars into missiles with all the guidance of a blind penguin.
The key thing to remember is that all weather in Forza Horizon 2 is actually dynamic. A given race may be bathed in sunshine, while the same race, later in the game, might feature a sunny start, followed by a momentary deluge, then a bone-dry race to the finish. In most racing games, weather has a less than realistic effect, but in the case of Forza Horizon 2, a sudden downpour translates to cars sliding off the road at 160 miles per hour. Once the rains come, you should be prepared to drive as cautiously as possible, lest your expensive ride turn into a rolling hunk of scrap.