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How to Calculate Sunset Time for Any Place

It's important to know when the sun will set if you are camping or hiking so you know when to establish camp or head for home. The time the sun appears to set depends on your precise location on the planet's surface -- it even varies slightly from town to town. The Astronomical Applications Department of the U.S. Naval Observatory provides a publicly accessible website for all sun and moon times, including rise, set and transit. Calculating the sunset time for a U.S. or international city is as simple as completing the form on the website.

Instructions

- 1
  Go to the Astronomical Applications Department of the U.S. Naval Observatory website for sun and moon data.
- 2
  Complete "Form A" for sun information in American cities or "Form B" for sun information in international locations. The date portion of each form is automatically filled out for today's date. Change the "Year," "Month" or "Day" fields if necessary.
- 3
  Select a state from the drop-down menu in "Form A" and type a city or town in box below if you are searching for times within the U.S. Spell out all prefixes such as "East," "Fort" and "Mount." "St." can be entered as is. Click "Get Data" when you are ready.
- 4
  Enter "Longitude," "Latitude" and "Time Zone" information into "Form B" if you are searching for an international location. Enter the name of the location in the "Place Name Label" box. This information will not be used in any calculation; it merely labels the top of the sun and moon calculations sheet on the next page. Click "Get Data" when you are ready.
- 5
  Read beneath the "Sun" heading on the results page. "Sunset" and "End Civil Twilight" times are displayed for the location and date you entered. Civil twilight is the time with the most light in the sky after the sun has officially set or before it breaks the horizon at sunrise. At the end of civil twilight the light begins to fade rapidly. The Civil Twilight time given assumes clear weather.

Astronomy