By Andreas Vollbrechtshausen
When exactly does autumn start? Quite simply: on two dates in September. The reason: A distinction is made between the calendar and meteorological beginning of autumn.
For meteorologists – that’s easy to explain – autumn always lasts from September 1st to November 30th.
However, the calendar (or astronomical) autumn only begins when the sun is vertically above the equator.
That happens this year on September 23 at 3:03 am. On Friday, day and night are about the same length. After that, the days get shorter until the beginning of winter on December 21, 10:47 p.m.
The timing of the change of seasons shifts from year to year because the earth rotates exactly once in 23 hours, 56 minutes and 4 seconds (and not in 24 hours). It takes 365 days, 5 hours, 48 minutes and 46 seconds (not 365 days) to orbit the sun once.
The fountain in the Lustgarten in front of the Altes Museum in Mitte will continue to gush until mid-October Photo: Stefanie Herbst
Because the astronomical year is slightly longer than the calendar year, a leap day is added at the end of February every four years to compensate for this inaccuracy.
Pleasant temperatures, golden light: After a hot summer, autumnal weather is good Photo: Stefanie Herbst
Enough astronomy, let’s enjoy the last days of summer (in the calendar sense). The German Weather Service expects daily temperatures of 16 to 18 degrees as well as sun and clouds by Friday.
At 4 to 8 degrees, the nights are already significantly cooler: This is what a typical Indian summer looks like.