Ultraviolet, or UV, radiation. You can't see it coming. But you can keep a lookout for it, thanks to a nifty little gadget called the SunMate.
The sun's invisible ultraviolet rays are ultra-villainous — known
Enter the UV Index, a scale from 1 to 11+, that tells you the level of UV radiation at any given time, which, in turn, tells you how risky it is to be out in the sun.
You can keep tabs on the index level for your city or ZIP Code at http://www.epa.gov/sunwise/uvindex.html. You can also subscribe to daily forecasts by email (at https://enviroflash.epa.gov/uv/Subscriber.do?method=start) or download an app for your phone (at http://www.epa.gov/sunwise/uviresources.html).
Most convenient of all, perhaps, you can get a SunMate. "Pull it out and push a button," says Myron Mullins, chief executive of Purely Products, which makes the gizmo.
The UV scale on the SunMate is the same as the UV index, except compressed. (It ranges from 1 to 5.) Tests prove it's extremely accurate and consistent, Mullins says. "And it's very, very durable, impervious to rain, salt, sand or wind."
A SunMate can be yours for $9.99 at http://www.purelyproducts.com. "Our goal," Mullins says, "is to take very cool technology and make it affordable."