diff --git a/modules/util/lon_lat_grid.py b/modules/util/lon_lat_grid.py
index d1a4e724070bb7ade28e1ac58c3058fa5f6837a4..40274abaf43a04c18d4651891d6c0660119d8b92 100644
--- a/modules/util/lon_lat_grid.py
+++ b/modules/util/lon_lat_grid.py
@@ -20,7 +20,7 @@ class LonLatGrid:
     # grd_lons, grd_lats: the longitude, latitude of each grid point (must be 2D grids), must have same shape
     # Incoming longitude must be in range: 0 - 360 degrees
     # Can have NaN for off Earth grid points (these are handled internally).
-    # closeness_threshold: if < distance of located_point to target, return off grid
+    # closeness_threshold (m): if < distance of located_point to target, return off grid
     def __init__(self, grd_lons, grd_lats, closeness_threshold=2000, reduce=1, leaf_size=40):
         if grd_lons.shape != grd_lats.shape:
             raise MyGenericException('incoming lons,lats must have same shape')