We apologize for the instability of composr.app and appreciate your patience. We are working on the statistics addon and trying to find an optimal way to store and render data. Unfortunately, we have yet to find a solution that can handle the traffic (and therefore, tens of millions of statistical records) of composr.app. We're working hard on one.
A review tells me that the only viable choices now are...
OpenWeatherMap (which is what I've implemented)
https://www.weatherbit.io/
https://www.apixu.com/
https://darksky.net/dev
https://www.5dayweather.org/
http://www.myweather2.com/
https://developer.yahoo.com/weather/ -- now needs oAuth, which seems excessive, and I don't trust Yahoo not to completely drop the API completely soon
https://www.metaweather.com/ -- someone's side project, so not sensible to integrate
A review tells me that the only viable choices now are...
OpenWeatherMap (which is what I've implemented)
https://www.weatherbit.io/
https://www.apixu.com/
https://darksky.net/dev
https://www.5dayweather.org/
http://www.myweather2.com/
https://developer.yahoo.com/weather/ -- now needs oAuth, which seems excessive, and I don't trust Yahoo not to completely drop the API completely soon
https://www.metaweather.com/ -- someone's side project, so not sensible to integrate