diff --git a/lib/xmet/hodograph.py b/lib/xmet/hodograph.py
index b3f2100..d1c3c2b 100644
--- a/lib/xmet/hodograph.py
+++ b/lib/xmet/hodograph.py
@@ -158,6 +158,9 @@ class Hodograph():
             if sample.pressure < 0 or sample.pressure is None:
                 continue
 
+            if sample.height is None:
+                continue
+
             color = self.color(sample.height)
 
             if color is None: