diff --git a/Doc/library/locale.rst b/Doc/library/locale.rst
index cc1f5b427accbd..61ca31623108e6 100644
--- a/Doc/library/locale.rst
+++ b/Doc/library/locale.rst
@@ -484,6 +484,9 @@ The :mod:`locale` module defines the following exception and functions:
    system, like those returned by :func:`os.strerror` might be affected by this
    category.
 
+   This value may not be available on operating systems not conforming to the
+   POSIX standard, most notably Windows.
+
 
 .. data:: LC_NUMERIC