Hi!
I too like Windy Weather very much. Most live wallpapers for Android come in dark colors, Windy Weather is very... joyful. Unfortunately the way it updates itself (the weather) is kind of annoying. The shortest interval it can be set to is 1 hour, but even that only works if at the exact moment when the hour changes you have an internet connection. I like to use WiFi and mobile data connections only when necessary (mostly off), so Windy Weather almost never updates itself automatically. I'd love a feature which would make it update whenever an internet connection is detected.
Answering the original question, manual update is available via the AccuWeather widget. Unfortunately that too is problematic. Sometimes hitting the update icon on the widget has no effect for hours (probably their server is not responding). Also, the widget occupies half a screen, which is kind of annoying. So yes, I'd love to be able to manually update it without the widget...