diff --git a/engine/table/src/main/java/io/deephaven/engine/table/impl/updateby/UpdateByOperatorFactory.java b/engine/table/src/main/java/io/deephaven/engine/table/impl/updateby/UpdateByOperatorFactory.java
index f129838dc51..a7696060696 100644
--- a/engine/table/src/main/java/io/deephaven/engine/table/impl/updateby/UpdateByOperatorFactory.java
+++ b/engine/table/src/main/java/io/deephaven/engine/table/impl/updateby/UpdateByOperatorFactory.java
@@ -1284,7 +1284,7 @@ private UpdateByOperator makeRollingWAvgOperator(@NotNull final MatchPair pair,
             final Class<?> weightCsType = weightColumnSource.getType();
 
             if (!rs.weightColumnApplicableTo(weightCsType)) {
-                throw new IllegalArgumentException("Can not perform RollingWAvg on weight column type " + csType);
+                throw new IllegalArgumentException("Can not perform RollingWAvg on weight column type " + weightCsType);
             }
 
             final String[] affectingColumns;