WDR 4 is a German radio station that is part of the Westdeutscher Rundfunk (WDR) media group. It is based in Cologne and primarily plays music from the 1960s to the present day. The station also features news, traffic updates, and other programming. WDR 4 can be listened to on the frequency 92.1 FM in the North Rhine-Westphalia region, as well as online through its website or a radio app.