Originally Posted by
Medic Zero
Isn't this pretty variable depending on where you are in the world? Sailors always talk about the sun disappearing quickly in the Pacific...
Yes, extremely variable. I guess I should have been more specific. That approximation seems to work around the continental USA. Obviously, it didn't work on the Alaska Highway, where the sun just sort of goes around in circles. But give it a try and see if it works for you.
On flat terrain it really isn't that useful, as the sun will set pretty much the same time as the night before. But it is useful in the mountains, when the sun may go behind a big ridge an hour or two earlier than "sunset".