Airports that have control towers also have a service called ATIS, for Automated Terminal Information Service. The ATIS is a radio broadcast on a dedicated frequency, updated whenever weather information is received (typically, every hour), and gives that information, along with what runways are in use and other information of interest to pilots arriving or departing from that airport. Each ATIS broadcast has an identifying letter associated with it, and a pilot is supposed to let the tower know the identifier on initial contact so the tower knows whether he's got the current information.
Heard at Green Bay recently:
"Advise on initial contact that you have information Delta. I'm Green Bay Ground Control, and I approved this ATIS."