Jens and all,
I understand you now.
I was just reading a few days ago, (and cannot remember where!), that there are different calendars still used in India, and in two of them, the year starts in spring, (was it march?)but on different days and in another calendar, the year starts in October or something!
Of course, neither March or October are used, that is merely for our benefit.
How this works in practical terms I am not sure.