I use that all the time. My wife is from northern Wisconsin and had never heard it before. First time I said,"Well it's about supper time." She paused, looked puzzled for a few seconds and said,"What is supper?" I looked back at her, puzzled,"You, you don't know what supper is? You don't eat supper? She said,"Oh you mean dinner?" I told her,"Dinner is in the afternoon, but now it's supper time."