Weatherunderground hater here. There are a large number of stations (Ambient Weather is a big seller in the US) that hook up neatly and conveniently to only supply data to wunderground.
But then you are 100% reliant upon them for their graphs and app displays, which are slow and often broken, and give you little choice in formatting. For example, the app doesn't display a wind history at all, but the web does. But it won't display on a variety of mobile devices very well.
I know they're free (at the advertising level anyway) but I would love to see some competition with better display options and broader browser / device support.
I currently "tee" my transmissions through another server, but only because I have a model of station (no longer made) that made this trivial. Now you have to intercept the RF which is much more of a pain.
https://www.pwsweather.com/ is another alternative to wunderground. Lately weatherunderground has kind of sucked - it has been down for a while, and rather slow -- and I the deprecation of the old API after IBM bought them was a pain to deal with. Still, their API is public, and the data that weatherstations send to it can be intercepted and used in your own system, for example openhab or home assistant.
