Anything I can to help? Im actually an Air Force aviator trying to get a module like this for our Operations Center.
There is a universal coding standard for METARS in the Flight Information Handbook (FIH).
Also, I’d stick to ICAO identifiers as they automatically include international.
If you use the API from NOAA: https://aviationweather.gov/metar/data?ids=Rodn&format=raw&date=0&hours=0, the results always come imperial.