I needed weather data on a wordpress page and all the plugins I found were not flexible enough for my needs. Then I discovered by accident the google weather API, which was basically just what I needed, but unfortunately there doesn't seem to be an official documentation. Thankfully I discovered the Web-Spirit
page (in german), which explains the whole thing thoroughly, including examples and a great function to call the google API. There is a problem when trying to get the weather for an austrian city, but the solution is pretty simple:
$wetter =website_wetter("", "Austria", "de", "Linz");
And it works!