Current versions of JavaScript do not always report the correct time zone, for one of several reasons.
First, if Daylight Time is in effect on the system, this causes a one hour error in the reported time zone.
Second, Internet Explorer, Netscape 3 and 4, and Netscape 2.0 do three different things with this quantity. Netscape Navigator 3 and above reverse the sign of the time zone, so people who live in the Western Hemisphere appear to be living in the Eastern Hemisphere and vice versa. A value of GMT +1 means that you are one hour ahead of GMT, as in Britain during British Summer Time.
All we can say is, our form tries to get the correct time zone value, but it will not be correct on some browsers. You may have to manually select your time zone. Make sure it is correct, as otherwise you may be called when you don't want to be.
Some examples of cities and their time zones to get you on the right track:
Also, remember to subtract one for Local summer time (ie. British summer time is GMT -1)