Index: Doc/library/time.rst
===================================================================
--- Doc/library/time.rst	(revision 77986)
+++ Doc/library/time.rst	(working copy)
@@ -149,9 +149,9 @@
 
 .. data:: altzone
 
-   The offset of the local DST timezone, in seconds west of UTC, if one is defined.
-   This is negative if the local DST timezone is east of UTC (as in Western Europe,
-   including the UK).  Only use this if ``daylight`` is nonzero.
+   When :const:`daylight` is nonzero, ``altzone`` specifies the offset of the
+   local DST timezone, in seconds west of UTC. This is negative if the local
+   DST timezone is east of UTC (as in Western Europe, including the UK).
 
 
 .. function:: asctime([t])
@@ -204,9 +204,16 @@
 
 .. data:: daylight
 
-   Nonzero if a DST timezone is defined.
+   Whether or not DST is in effect, ``daylight`` specifies the DST offset.
+   The value will be nonzero in timezones which experience DST.
+   
+   .. note::
 
+      This is not useful for determining if the system is currently in DST.
+      Rather, you should check the :const:`tm_isdst` member returned by
+      :func:`localtime`.
 
+
 .. function:: gmtime([secs])
 
    Convert a time expressed in seconds since the epoch to a :class:`struct_time` in