How to Calculate Sunrise and Sunset



  • To compute sunrise and sunset times is easy, you just need to apply the following formula:

    formula sunrise.jpg

    where:
    ωo is the hour angle in degrees at either sunrise (when negative value is taken) or sunset (when positive value is taken) in degree (°)
    φ is the latitude of the observer on the Earth in degrees
    δ is the sun declination in degrees

    Alternatively, you can use sunrise/sunset times on Windy.

    author:windy.com;licence:cc;link:https://www.windy.com;

    Following contour plot shows hours of daylight based on latitude and day of the year.

    licence:cc;link:https://en.wikipedia.org/wiki/Sunrise_equation#/media/File:Hours_of_daylight_vs_latitude_vs_day_of_year_cmglee.svg;desc: A contour plot of the hours of daylight as a function of latitude and day of the year, using the most accurate models described in this article. Latitude 40° N (approximately New York City, Madrid and Beijing) is highlighted for reference.;

    For more information about sunrise & sunset, I recommend Astronomical Applications Department of the U.S. Naval Observatory website.


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