Correct way to write out a date range in German

Question

What is the best way to write out a date range in German?

For example, something takes place on 05. September 2015 which is how I've come accustomed to seeing it in Germany. I'm not sure as to why the point is used after the number? When writing out a date range, my colleague sent me this:

05.–30. September 2015

Why do we use the points? Typographically it looks redundant. Just want to know the reasoning as 05–30 September 2015 looks cleaner, but not sure how to present this to my German native colleagues who are stern about this topic.

Answer 1

Because the point of the point (pun intended) is to give the ordinal number instead of the cardinal number.

Interestingly enough, English does use ordinal numbers for days when writing "on the fifth of May", or "May 5th" but omits the ordinal marker for dates like 05-05. German is more consistent as it always uses the '.' (Except for the YYYY-MM-DD format which is seldom used in day-to-day writing.) Please note that if you write the month as a number, it's ordinal as well: 05.05.

So your collegue could have written "05. - 30. September" or "05. - 30.09."

Answer 2

We use the point to get the ordinal, not cardinal number. Compare:

der 1. Platz (=der erste Platz)

Straße des 17. Juni (=des siebzehnten Juni)

That's why we must use the point in dates.

According to the range - these would be some common ways of giving a time period:

5. - 30. September 2015

vom 5. bis (zum) 30. September 2015

vom 5. - 30. September 2015 (which I personally don't like because you mix a preposition with symbolic dash character, but it's very common)