Compared to weather balloons, it's quite a bit more data. In the U.S. there are only 91 weather balloon launching sites, so that's 182 observations per day. A

Compared to weather balloons, it's quite a bit more data. In the U.S. there are only 91 weather balloon launching sites, so that's 182 observations per day. AMDAR has 700 aircraft, and each one probably makes about 4 flights per day, and they get a temperature profile going up and going down, so that's 5600 profiles per day. There are about 450 airports in the U.S. with regular commercial service, and the majority of these are covered.