Time in Emacs status bar

When emacs show the time in the status bar, the time zone is not correct.
I have tried to correct it by putting this in ~/.emacs:

(set-time-zone-rule "GMT+2")
(setq display-time-day-and-date t
display-time-24hr-format t)
(display-time)

But for example the time now is 16:00 in our time zone but emacs shows
12:00.

How do I convince emacs to use the same time zone info as the system?

Regards
Johann