A radio format or programming format (not to be confused with broadcast programming) describes the overall content broadcast on a radio station. In countries where radio spectrum use is legally regulated (such as by OFCOM in the UK), formats may have a legal status where stations are licensed to transmit only specific formats.
Radio formats are frequently employed as a marketing tool, and are subject to frequent change. Music radio, old time radio, all-news radio, sports radio, talk radio and weather radio describe the operation of different genres of radio format and each format can often be sub-divided into many specialty formats.
Formats constantly evolve and each format can often be sub-divided into many specialty formats. Some of the following formats are available only regionally or through specialized venues such as satellite radio or Internet radio.
Seasonal formats typically celebrate a particular holiday and thus, with the notable exception of Christmas music (which is usually played throughout Advent), stations going to a holiday-themed format usually only do so for a short time, typically a day or a weekend.
In some countries such as the UK, licences to broadcast on radio frequencies are regulated by the government, and may take account of social and cultural factors including format type, local content, and language, as well as the price available to pay for the spectrum use. This may be done to ensure a balance of available public content in each area, and in particular to enable non-profit local community radio to exist alongside larger and richer national companies. On occasions format regulation may lead to difficult legal challenges when government accuses a station of changing its format, for example arguing in court over whether a particular song or group of songs is "pop" or "rock".