Datetime field in Image Information module

Hi all,
I notice that the datetime field in the image information module shows both the date and time the image was taken (coming from the camera) and also a time zone offset (for me currently +0200). I also noticed that for images taken a few months ago the offset was +0100, which makes sense, since we have summer time now. But the problem is that my camera doesn’t have any idea about the time zone, so where does that info come from? My guess is that it comes from my computer at import time, but this does not necessarily have any relation to the time zone where the images were taken. Does anybody know?

Are you sure you didn’t set the time zone? Both of my Nikon’s and Canon know of the time zone.

This is Canon 550D/T2i, which does not have a time zone setting.