first of all thanks a lot for the answers.
I had already come across the AS3935 sensor somewhere and it is not expensive either.
However for 1-wire I have the stuff and experience with it.
If I take i2c/spi then I have to find out again how I can get the data on the computer where the weather display is running.
unless it can be done with a simple arduino via the serial monitor, because arduino I still have a lot of lying around so I can sacrifice one of them.