WWSN (97.5 FM, "Sunny FM") is a radio station broadcasting an Adult Contemporary format. Licensed to Whitehall, Michigan, the station serves the Muskegon, Michigan market. The station's programming is derived from Cumulus Media Networks' Hits & Favorites format. It is heard as far Grand Rapids, Michigan, east Of US-131, and it experiences interference from WJIM-FM from Lansing. The station began broadcasting in 1991 as WPBK-FM with a satellite-fed country format from Unistar Radio Networks, and became WEFG-FM ("Frog") soon afterward. In 1995, WEFG's format changed to a 1970s-based classic hits format (as Eagle 97.5) satellite-fed from Westwood One.