A weather radio is a specialized radio receiver that is designed to receive a public broadcast service, typically from government-owned radio stations, dedicated to broadcasting weather forecasts and reports on a continual basis, with the routine weather reports being interrupted by emergency weather reports whenever needed. Weather radios are typically equipped with a standby alerting function—if the radio is muted or tuned to another band and a severe weather bulletin is transmitted, it can automatically sound an alarm and/or switch to a pre-tuned weather channel for emergency weather information. Weather radio services may also occasionally broadcast non-weather-related emergency information, such as in the event of a natural disaster, a child abduction alert, or a terrorist attack.
They generally broadcast in a pre-allocated very high frequency (VHF) range using FM. Usually a radio scanner or a dedicated weather radio receiver is needed for listening, although in some locations a weather radio broadcast may be re-transmitted on an AM or FM broadcast station, on terrestrial television stations, or local public, educational, and government access (PEG) cable TV channels or during weather or other emergencies.