Skip to content
WC Leung edited this page Oct 11, 2023 · 9 revisions

This app displays the sunrise and sunset times, and also the civil twilight times.

How to use the app?

  • Open the app by choosing one of the badges below (if you are not already using it):

    Get it on Google Play   Open in any browser

  • Allow the use of location. (Or manually enter the latitude and longitude.)

  • Now you can find the predicted sunrise, sunset and civil twilight times.

  • Civil twilight times are more useful to see if there is sunlight, while sunrise and sunset times is for you to observe the sun. There is some sunlight even when the sun is below the horizon.

What do the results mean?

Sunrise and sunset times

The sunrise and sunset times in the app are calculated with an algorithm. The actual sunrise and sunset times depends on actual atmospheric conditions, which cannot be predicted by calculations. Therefore, the actual sunrise and sunset times can differ from the calculated times by a few minutes.

For details about the algorithm used, read NOAA Sunrise/Sunset and Solar Position Calculators.

Civil twilight

Some sunlight, known as twilight, is present even before sunrise and after sunset due to sunlight scattering. During civil twilight sunlight is generally enough for outdoor activities.