diff --git a/activitysim/abm/tables/skims.py b/activitysim/abm/tables/skims.py
index 6cb20edc6e..3a2245278c 100644
--- a/activitysim/abm/tables/skims.py
+++ b/activitysim/abm/tables/skims.py
@@ -149,7 +149,7 @@ def block_name(block):
 def buffers_for_skims(skim_info, shared=False):
 
     skim_dtype = skim_info['dtype']
-    omx_shape = skim_info['omx_shape']
+    omx_shape = [np.float64(x) for x in skim_info['omx_shape']]
     blocks = skim_info['blocks']
 
     skim_buffers = {}