Calendar monthly view does not seem to use site time zone

I have a site which is hosted in the US, but I work in Europe. I installed the Calendar module and was testing it late at night (VERY late) on 30th November - in fact it was so late that I was still working in the early hours of 1st December. Imagine my surprise when I displayed the default monthly view (no arguments therefore), only to see it displaying the month of November instead of December as it should have done.
Now everything is ok, it displays December correctly, so the only explanation I can think of is that the Calendar module View was not using the site timezone (in which case it would have displayed December on 1st December at 02:00), but the system timezone which - since it is in the US - was several hours behind me.