Sunrise Sunset Times

Type a city to sea the sunrise, sunset time and daylength

Sunrise and Sunset Times: How they are Calculated and Why They Matter

The natural phenomenon of sunrise and sunset has been fascinating humans for thousands of years. In earlier times people used to rely on the sun to know the time of day and for navigation. Even today knowing the exact time of sunrise and sunset can be important for various reasons. It helps us plan our day and activities, especially if we are outdoors and it is crucial for activities like farming, fishing and hunting.

Calculation of Sunrise and Sunset Times

The calculation of sunrise and sunset times is based on the position of the sun relative to the observer's position on the Earth. The Earth rotates around its axis which takes approximately 24 hours to complete one rotation. This rotation causes the sun to appear to rise and set every day.

The position of the sun in the sky changes throughout the day and this position is measured using angles. The angle between the sun and the horizon is called the solar altitude angle. Sunrise and sunset times are calculated using this angle which varies depending on the latitude, longitude and altitude of the observer's position.

The solar altitude angle is also affected by atmospheric refraction which is the bending of light as it passes through the Earth's atmosphere. This bending causes the sun to appear higher in the sky than it actually is. This means that the sunrise and sunset times are slightly earlier than they would be without atmospheric refraction.

Why Sunrise and Sunset Times Matter

Sunrise and sunset times have several practical and cultural implications. Here are some reasons why they matter: