Weather Underground will retire its API at the end of 2018. Weather Underground was acquired by The Weather Company in 2012. The Weather Company was acquired by IBM in 2015. Now, IBM infrastructure is better suited to meet the enterprise-grade demands of the Weather Underground developer community.
Samsung and the Tizen Association recently made the Tizen Software Development Kit for Wearables available from the Tizen developer web site. The SDK supports any wearable running Samsung's Tizen operating system, but that's an extremely limited number of devices at the moment, with just the Samsung Gear 2 and Gear 2 Neo smartwatches filling the space.