Yes, given that Apple supposedly vets all of the apps they put on their app store, it would be very odd that they might be unaware of this going on. Furthermore, most of the folks here are amazed and happy about weather apps such as Dark Sky (I use it and like it as well) being so accurate. It truly is, down to your current GPS location during the day or night. I ask you, how in the world do you think they manage this without constant monitoring of your location data (which, of course, is even further enhanced with wifi enabled and running)? Here's a quote from Dark Sky's Terms of Service, under "Disclaimers":
"Your use of the Service is at your sole risk. <...> WE MAKE NO WARRANTY THAT OUR SERVICES WILL MEET YOUR REQUIREMENTS, BE SAFE, SECURE, UNINTERRUPTED, TIMELY, ACCURATE, OR ERROR-FREE, OR THAT YOUR INFORMATION WILL BE SECURE."
My point being, no mobile application which bases its accuracy upon your current, real time location, is secure, and most likely the metadata gathered - even if your exact name and personal information aren't preserved - is being used to generate at minimum information needed to target you and your location data for further marketing. The worst thing about the AccuWeather finding is that they continued to monitor your router information, your location, etc., even though you told them explicitly not to do so.