The Skywatch Windoo series of anemometers from Swiss company JDC Electronic SA pack wind- and weather-tracking power into your smartphone by way of a sleek, plug-in unit that's small enough to clip on to your keychain.

The Skywatch Windoo isn't the first anemometer smartphone accessory to hit the market. However, models like the Vaavud and Shaka have bulky housings that don't look particularly comfortable to carry around in your pocket, what with your phone, wallet and other things in there.

The Windoo, on the other hand, is a slim shaft that's about the size of a tube of lipstick. When the actual wind meter is popped out of its protective carbon case, it's smaller than a thumb, so it's easy to pop into any pocket. The 1.3-oz (38-g) device comes with a keyring and a wrist strap. Not everyone cares enough about the wind to carry an anemometer, but those that do – think kite surfers and boaters – could benefit from having a light, pocket-sized model on them at all times.

The battery-less Windoo plugs into your smartphone's headphone jack. Inside its aluminum housing, its tiny, multidirectional propeller spins in the wind with help from its stainless steel shaft and sapphire bearings, measuring wind speed and direction. Unlike some other smartphone anemometers that measure only wind, the Windoo family includes a Swiss-made sensor set for temperature (and wind chill), humidity and pressure readings. The device sends all the weather information to the accompanying smartphone app, where it can be viewed and stored/shared on Facebook, Twitter and Windoo's website. The app can also graph and map the data.

The Windoo tracks wind speeds up to 93.2 mph (150 km/h) with +/- 2 percent accuracy. We can't confirm JDC's claim of accuracy without testing first, but we do know that the Swiss know a thing or two about accurate tracking by way of small moving parts.

The Skywatch Windoo hit retailers this month in three different versions. The Windoo 1 is the most basic, combining wind speed/direction with temperature readings. The Windoo 2 adds a humidity sensor, and the Windoo 3 adds both humidity and pressure sensors. They retail for CH59, 79 and 99 (US$66, $89 and $111) for the 1, 2 and 3 models and are designed to work with a variety of iOS and Android devices.

Product page: JDC Electronic