If a MQTT (see WeatherFlow UDP listener and MQTT/InfluxDB publisher utility) is uses the time laps is so small, it doesn’t matter in the case of those weather data.
A VPN connection as a main part of a solution in between (a third option). But again, you have to be skilled to set one up and will have to use additional hardware.
A VPN will probably not pass UDP broadcasts, if that’s what is being suggested…
Thank you @eric and @dsfg for suggestions.
I will look into the API option. I have another setup with Hub, Sky and Air +RPi (with double wifi…, weewx) and works great. Here in this new setup I will not have the Air unit and would like to avoid another RPi and just take data from home location.
I’m not a rookie in the linux world but a complete rookie in this new world of IFTTT and other web services… 
It depends on the setup and the VPN-solution. If the only use case is to transfer the WF UDP data, there are solutions but, as I said, those a not for beginners.
Still not certain what you’re trying to accomplish. Draw us a picture please.
My UDP listener and @vreihen’s driver for weewx can process just about any UDP they can hear, and feed influxdb or MQTT or weewx (sqlite3 or mariadb etc.) just fine if you can get the packets to the computer doing the listening.
But the UDP is a broadcast, so it’s not routable in general. Those messages are going to stop at the first router.
You could definitely grab multiple stations by querying the WF servers with websockets, but that is not “reading hub data from a different subnet”. It’s not even “reading hub data” really. It’s reading the very processed stuff WF saves ‘based on’ hub data.
What @vreihen and I do is read the raw data off the hub and not need (or want) anything from the WF data at all. The other local solutions basically take the same approach.
So it really comes down to what problem you’re trying to solve. Again, draw a quick picture or something. If you need a free site online draw.io is pretty easy to use to generate a quick picture.
My original post was indeed referring to reading from a subnet in the home network but now I have a slightly different situation.
This is exactly what I want to do:
… and a scheme:
Thank you for your patience - I’m not a native English speaker and sometimes have difficulties to express my thoughts in a clear way.
I’d like to grab the Sky’s data which is already in the WF cloud (“blue web page with realtime update”) and store it in my RPi at home. I’d like to do it near real-time (e.g. once per minute).
Your English is excellent.
Sounds like the websockets interface. I think the WeatherFlow PiConsole works this way if I understand things. That would give you a nice display at home too. I don’t remember if this software saves data locally or not.
There are likely other packages out there too that people have written. Hopefully some reply too.
I might add the ‘store it locally’ can be done in a lot of ways. You could save to influxdb and display to grafana. You could use MQTT. Lots of possibilities depending on what complexity you are ok with.
I found my own way using REST. It’s very easy in fact… I have a bash/python script that takes data every minute -all I needed!
Thanks.