Forza Horizon 2 features a "super sexy weather system" and is due to release this autumn, according to an alleged Xbox insider.
Besides the new weather system, the informant also claims that the open-world racer will feature "shit tons of co-op/social stuff... so you can road trip with your bros".
They also say that it will "probably" release this September and runs at 1080p.
Forza Horizon 2 has long been rumoured to be in development, with original developer Playground Games thought to be heading up the project.
The latest whispers about the game spread from an update from supercar manufacturer Ultima, who revealed that it had "recently agreed a new contract with the Microsoft Corporation to be included in a new video game to be launched later in 2014".
The manufacturer has previous ties with Forza titles, having had its vehicles appear in Forza Motorsport 4 and Forza Motorsport 5.
Microsoft told VideoGamer.com that it does not comment on rumour and speculation when contacted about the leak this morning.