diff --git a/calsub/http.go b/calsub/http.go
index 476723463b..9bd89d3880 100644
--- a/calsub/http.go
+++ b/calsub/http.go
@@ -30,7 +30,7 @@ func (s *Store) ServeICalData(w http.ResponseWriter, req *http.Request) {
 		return
 	}
 
-	shifts, err := s.oc.HistoryBySchedule(ctx, cs.ScheduleID, n, n.AddDate(0, 1, 0))
+	shifts, err := s.oc.HistoryBySchedule(ctx, cs.ScheduleID, n, n.AddDate(1, 0, 0))
 	if errutil.HTTPError(ctx, w, err) {
 		return
 	}