diff --git a/Doc/library/exceptions.rst b/Doc/library/exceptions.rst
index 8cc887b8ceb378..9d3e0a4c20f9eb 100644
--- a/Doc/library/exceptions.rst
+++ b/Doc/library/exceptions.rst
@@ -890,6 +890,9 @@ The following exceptions are used as warning categories; see the
 
    Base class for warnings about dubious syntax.
 
+   This warning is typically emitted when compiling Python source code, and usually won't be reported
+   when running already compiled code.
+
 
 .. exception:: RuntimeWarning
 
diff --git a/Doc/library/warnings.rst b/Doc/library/warnings.rst
index 00bafd1be4bd0c..a2bb4b1830dec4 100644
--- a/Doc/library/warnings.rst
+++ b/Doc/library/warnings.rst
@@ -80,7 +80,9 @@ The following warnings category classes are currently defined:
 |                                  | unless triggered by code in ``__main__``).    |
 +----------------------------------+-----------------------------------------------+
 | :exc:`SyntaxWarning`             | Base category for warnings about dubious      |
-|                                  | syntactic features.                           |
+|                                  | syntactic features (typically emitted when    |
+|                                  | compiling Python source code, and hence       |
+|                                  | may not be suppressed by runtime filters)     |
 +----------------------------------+-----------------------------------------------+
 | :exc:`RuntimeWarning`            | Base category for warnings about dubious      |
 |                                  | runtime features.                             |