@env{TMP}, then @env{TEMP}, and finally @file{c:/temp}.
@item TZ
@vindex TZ, environment variable
-This specifies the current time zone and possibly also daylight
-saving time information. On MS-DOS, if @env{TZ} is not set in the
+This specifies the default time zone and possibly also daylight
+saving time information. @xref{Time Zone Rules,,, elisp, The GNU
+Emacs Lisp Reference Manual}. On MS-DOS, if @env{TZ} is not set in the
environment when Emacs starts, Emacs defines a default value as
appropriate for the country code returned by DOS@. On MS-Windows, Emacs
does not use @env{TZ} at all.