For anybody who stumbles across this review, there are a few ways to make this more reliable. Firstly the free version of this plugin uses OpenWeatherMap, which is an open source weather provider. The more we use their service the better it will get.
There have been problems with location lookups, there is a way to see if your city is available and then use the City ID directly to avoid this problems. Steps can be found here: http://halgatewood.com/docs/plugins/awesome-weather-widget/finding-city-id/
There is also a PRO version available that allows you to change your weather provider to Yahoo!. It is available here: http://halgatewood.com/downloads/awesome-weather-widget-pro/