Start building the house in October?

Shell construction only causes problems when the water on the construction site freezes!

Example 2014 winter in the Black Forest as warm as it hasn't been for decades, the following year the same! Construction continues.

With us, due to various delays, it only started in October. We are building in [Mittelhessen]. Tomorrow our basement will be delivered and the week after that the masonry of the ground floor will begin. The shell construction should be completely finished before Christmas. Let's see how the screed will turn out then.

I even find it advantageous to start in autumn, as the shell construction can then dry well over the winter. But above all, you will probably move in during the summer and not at -20 degrees ;) And the screed heating phase also runs at warmer outdoor temperatures, which is not an insignificant cost factor.

...since the shell construction can then dry well over the winter.

Is that even relevant nowadays? I think I heard that moisture input during masonry is by far not as high as it used to be.

Regardless, the point about the screed and especially moving in during summer is good [emoji4]

Is that even relevant nowadays?

Not relevant, thin-bed installation or even gluing is used.

the point about the screed and especially moving in during summer is good

I find it rather the opposite... Summer means high humidity and poor screed drying. In addition, after the heating program has been run in autumn or winter, the house has a base heat. That's something I don't want in summer.

Building physics states that screed dries best in winter. Cold air enters the house with low humidity, gets warmed by the heating system, and can absorb a lot of moisture.

When cross-ventilating, you then exchange the warm moist air for the dry cold air (~35% humidity). In summer, the air naturally has 68 ~ 75% humidity at 30 degrees, so you do not have nearly as much absorption potential as in winter.

This is also the reason why a cold floor mold develops if you always leave the pull-down staircase open.

The warm air rises into the cold floor, which reaches about 30 degrees when exposed to sunlight and holds a lot of moisture. At night, the temperature drops to, for example, 10 degrees, the air cannot hold as much moisture, the water condenses, and goes into the beams or insulation wool.