For anyone stumbling upon this thread:
It is actually possible to set weather status location programmatically via the occ command per user:
occ user:setting -- $user weather_status address "$City, $Country"
occ user:setting -- $user weather_status altitude $altitude
occ user:setting -- $user weather_status lat $latitude
occ user:setting -- $user weather_status lon $longitude
occ user:setting -- $user weather_status mode 2
The correct values can determined e.g. from another user where the desired location has already been set via the GUI:
occ user:setting -- $user_where_already_set weather_status