This Weather Underground iOS and iOSX library developed by Mendy Krinsky provides access to the API in mobile and desktop devices. To begin, users need the Wunderground API key. Then, they can proceed to obtain climate's current conditions, receive forecast for the next 36 hours, and retrieve data for the following 3 days with an additional summary. Instructions to use with CocoaPods available. Under MIT license.
The HQCasanova Weekly CO2 API is incredibly simple. It's also a frighteningly clear measurement of how our planet is doing. It measures the level of CO2 in the air in parts per million (ppm), a major player in causing global climate disruption.
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.