Flight Watch is the common name in the United States for an Enroute Flight Advisory Service (EFAS) dedicated to providing weather to and collecting from pilots while in flight.
While U.S. Flight Service Stations (FSS) operate Flight Watch, Flight Watch does not provide a full range of FSS services such as filing flight plans, acquiring preflight weather briefings, providing NOTAMs, or picking up IFR clearances; instead, it is limited to the following:
The service is available on a single common frequency, 122.0 MHz, to flights operating below Flight Level 180 (18,000 feet MSL) from 06:00 to 22:00 local time across the conterminous United States[1]. Discrete frequencies are available for high altitude aircraft (at and above 18,000 feet MSL, or FL180), based on location. Flight Watch may be unavailable below 5,000 feet AGL, depending on terrain and the distance from the nearest station.