diff --git a/modules/icing/pireps.py b/modules/icing/pireps.py
index fa2ce9bdb9312a4663ea43c1cd040d46cb9ee8c4..a869c55753eaf46797dea5d913d93f66138b47af 100644
--- a/modules/icing/pireps.py
+++ b/modules/icing/pireps.py
@@ -18,7 +18,7 @@ ATYPE = '/TP'
 RMK = '/RM'
 
 
-# Returns icing/no_icing/neg-icing
+# Returns icing, no_icing (no icing observed), neg-icing (icing expected, but not observed)
 def pirep_icing(filename, lon_range=[-180, 180], lat_range=[-55, 55]):
 
     # HEADER: VALID,URGENT,AIRCRAFT,REPORT,LAT,LON