Historical meteodata back till 1980 (depending on the station) are available here (page only in German):
I created a weewx import config file 'meteoschweiz.conf' for these data from a specific station. The conf file needs to be modified for the file to import (path+filename). I selected data with a time period of 60min on the website and for the import.
Usage to test: weectl import --import-config meteoschweiz.conf --dry-run
Usage for import: weectl import --import-config meteoschweiz.conf
Regards Matthias