The Wetter is a small 69 km long river in Hesse, Germany and right tributary to the Nidda. After leaving the Vogelsberg mountain range the river flows through the Wetterau, a fertile landscape just north of Frankfurt, which is named after the river. The principal towns the river along the river are Laubach, Lich, Bad Nauheim and Friedberg. The Wetter receives its largest tributary, the Usa, at Friedberg just before it finally joins the Nidda at Niddatal-Assenheim.