Previewed at WWDC, launching in the fall.
iOS 8 Ditches Yahoo Weather for Content From The Weather Channel
Yahoo's weather information, however, was also supplied by The Weather Channel (TWC), so it seems that Apple has opted to cut out Yahoo as a go-between. The switch from Yahoo to TWC is a bit surprising given reports of ongoing talks between Yahoo and Apple over ways to more deeply integrate Yahoo services into iOS apps. While it is unclear if those plans have been scrapped, an April report suggested Yahoo was aiming to revamp its mobile search platform with the hopes of being iOS's default search engine.
While the source of the data Apple uses is ultimately the same, there are differences in the underlying technology supporting the weather data between the two services. Because of that, the data presented to the end user may be slightly different even though Yahoo also obtained its data from TWC.
In addition to using TWC as a source for weather data, the iPhone's weather app is now displaying a nine day weather forecast, up from the previous five day forecast. There's also a new weather summary at the bottom of the app, noting the current weather conditions along with conditions for the rest of the day.
The new Weather app within iOS 8 is currently available to registered developers. The general public will get access to the operating system this fall, after beta testing has been completed.