Weather in Space

The Sun

How is the time set for the beginning of sunrise and sunset?

In the United States, sunrise officially begins when the leading edge of the Sun disc first begins to rise over the horizon; and sunset happens when the top of the Sun disappears behind the horizon. In Great Britain, however, sunrise and sunset are measured by the time when the middle of the Sun is at the edge of the horizon. Scientists use highly sensitive light-measuring instruments to calculate when dawn is approaching as much as 90 minutes before sunrise actually occurs.


This is a web preview of the "The Handy Weather Answer Book" app. Many features only work on your mobile device. If you like what you see, we hope you will consider buying. Get the App