The program takes into account your skin type, the weather and the UV index of your current location. The SPF of a sunscreen that you're using, is considered also. Freckles automatically resolves your current location and retrieves weather conditions and the UV-Index. After you have set your skin-type and your age, Freckles calculates the time you can stay in the sun, without the risk of getting sunburned. Skin-type and age is saved between subsequent calls, so you only have to enter it the first time. You also have the ability, to set the SPF of a sunscreen, you might be using. You can instantly see, how much even a low SPF increases the time you can stay in the sun. After the time is calculated, you can start a timer, that sounds an Alarm, as soon as the time expires. During the "countdown", a Analog Stop-Watch is animated and a running noise (Tick-Tack) is played. Of course, this sound can be muted, if you don't like it. You may interrupt the running timer, at any time and do other things with your iPhone/iPod-Touch. After Freckles is started again, it recalculates the the remaining time automatically.
iPhone OS 3.x