The API key can be removed by following the steps here you can remove it: https://opensprinkler.com/forums/topic/no-more-free-wunderground-api-key/page/4/#post-54166
However, please note there is no reason to remove it really. The Weather Service API will ignore that key now and always use OpenWeatherMaps. Regarding the quality we are working to improve our data from OWM.