Speaking as someone who lives in Germany, this is a common sentiment from old timey Germans that hasn’t been true for awhile. It’s far more than a week every year and it’ll only get worse.

It’s like the memory of the past is so strong it overwrites the present day experience. I think the truth of the matter is home ownership is so low that installing AC is never even considered by the owning class. Germans definitely have a culture of not needing AC and like superstitiously not liking them, but honestly California had similar beliefs when I lived there but they had just started to cave to the present reality. I think Germany is a decade behind on this matter and in 10 years 80% of the population will have AC and the last 20% will be the people whose landlords refuse to invest in their properties and blame it on the infrastructure not being built for AC.