diff --git a/lib/microwaveprop/propagation.ex b/lib/microwaveprop/propagation.ex
index 9db4318c..e2a5c14b 100644
--- a/lib/microwaveprop/propagation.ex
+++ b/lib/microwaveprop/propagation.ex
@@ -18,6 +18,16 @@ defmodule Microwaveprop.Propagation do
 
     temp_c = hrrr_profile.surface_temp_c
     dewpoint_c = hrrr_profile.surface_dewpoint_c
+
+    # Skip points with missing surface data (ocean/outside-domain)
+    if is_nil(temp_c) or is_nil(dewpoint_c) do
+      []
+    else
+      score_grid_point_with_data(hrrr_profile, valid_time, temp_c, dewpoint_c, derived)
+    end
+  end
+
+  defp score_grid_point_with_data(hrrr_profile, valid_time, temp_c, dewpoint_c, derived) do
     temp_f = Scorer.c_to_f(temp_c)
     dewpoint_f = Scorer.c_to_f(dewpoint_c)