since you are already collecting data from the weather station in python, it should be simple for you to turn that python code into a weewx driver.
take a look at the fileparse driver that ships with weewx. instead of reading from file, substitute the code that you are already using to read from the hardware. instead of emitting json, you simply add to a dict the observations as named elements.
the fileparse driver is packaged as an extension, i.e., it has a readme, changelog, install.py as well as the fileparse.py driver itself. you only need to do that packaging if you want to distribute your driver in an easy-to-use package.
see the weewx customization guide for details:
http://weewx.com/docs/customizing.htm#portingsee the weewx wiki for many other driver examples:
https://github.com/weewx/weewx/wiki#driversm