There is a growing concern in the community about solar access and overshadowing of public and private open space in urban areas as the density and the height of buildings increase. All methods of analysis require a knowledge of the relative position of the sun. This paper addresses the order of accuracy of this knowledge to highlight the limitations of its predictive power. Some graphical methods have been produced for nominal locations, e.g. 35degS and 150degE, but are applied to precise locations, e.g. the Central Business District of Sydney, Australia. When arguments relate to limited periods of the day, for example “lunch time”, the small differences between the real and nominal location could result in a proposed development application being denied.