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    How to Calculate Sunrise and Sunset

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    • T
      TomSlavkovsky API developers | Premium
      last edited by Simona Polackova

      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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