There is an old rule of thumb that says that if the bottom of the sun is resting on the top finger of your outstretched hand when your hand is resting on the horizon - then its about an hour until sunset.
Well, with the technology in the iPhone, we dont need rules of thumb any longer - you can get the exact time from your hand for your location and time of year!
The height of the sun changes constantly throughout the year, and also depends on your latitude. The visual height of your hand depends on the width of your hand, as well as the length of your arm.
With Sunset Timer, you can calculate the time until sunset from your hands at any location on earth, and at any date.
Instead of:
"Not long until sunset, wed better hurry!"
You can now:
"Based on my calibrated hands for this general location and season, we have almost an hour and a half until sunset. Plenty of time for another drink!"
[Obvious but important warning: Do NOT stare at the sun while using this app or at any other time. A quick glance with your peripheral vision gives you an idea of where the sun is relative to your hand.]