NextGen Weather, also known as the NextGen Weather Program, is part of the Federal Aviation Administration's (FAA) ongoing Next Generation Air Transportation System (NextGen) infrastructure program to modernize the U.S. National Airspace System (NAS). The intent of NextGen Weather is to reduce the impact of weather on aviation, resulting in safer, more efficient and predictable day-to-day NAS operations. Weather is the largest cause of air traffic delay in the NAS.