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How to Calculate The Sun's Altitude

The Earth rotates around its axis and around the sun. The spinning of the earth on its access is what causes day and night and the apparent movement of the sun across the horizon. The Earth's orbit around the sun takes just over one year to complete and is responsible for variations in the sun's altitude at various points throughout the year. The Earth is farthest from the sun on July 4 and closest on January 3. If you want to know the sun's altitude from the earth, you can figure it out with a simple calculation.

Things You'll Need

Computer with internet connection
Calculator

Instructions

- 1
  Understand that solar altitude is measured from the southern or northern point along the earth's horizon; measurement begins at zero degrees and reaches a maximum of 90 degrees when the sun is directly overhead.
- 2
  Use the attached chart (See References) given your starting latitude to quickly find the sun's altitude during the June and December solstices or the March and September equinoxes.
- 3
  Calculate the altitude of the sun at solar noon for any starting latitude point with the following equation:
  
  A = 90 - L +/- D
  
  where A = altitude, L = latitude and D = declination. Enter the latitude of your starting location in degrees. Add D to L if the starting latitude is experiencing summer at the time of calculation; subtract D from L if the starting latitude is experiencing winter. Values for D are equal to 23.5 on the June and December solstices and 0 on the March and September equinoxes. Reference the table of the declination of the sun (Ref. 2) for declination values on other days.

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