Using the equations on the previous page, the position of the sun in the sky can be determined from the observer's location and the time of day. In the top blue squares, enter the observer's location and time of day. An alternate calculator for the sun's path is also available at the PV Lighthouse Solar Path Calculator
Time and Date
The time is given as 24 hour time and the minutes are entered separately. Thus for 5:15 pm, enter 17 in the hour box and 15 in the minute box.
Longitude, Latitude and Time Zone (GMT)
Longitude, latitude and time zone of locations throughout the world are available at www.timeanddate.com. Minutes of longitude and latitude are entered as fractions, so 17° 30' becomes 17.5. Enter locations with an west longitude as negative. For daylight saving (summer time), subtract 1 hour from the given values. Generally speaking, locations east of Greenwich (UK) are positive and locations west of Greenwich are negative.
There are other services that will determine your approximate latitude and longitude from your IP address. For example ip2location.com. For a given latitude and longitude http://timezonedb.com/ will calculate the GMT offset.
Explanation of polar plots
The most convenient way to plot the sun's position throughout the day is on a polar plot. Click on the animation for an explanation of these polar plots.