Shade Planning for Schools

35 Shade Planning for America’s Schools Chapter 5 The Sun’s Annual Path and the Creation of Shade Shadows cast by the sun grow longer from June 21st until December 21st, and then grow shorter from December 21st until June 21st. This is a result of annual changes in the solar altitude angle. The change in shadow length is depicted graphically in the following illustration. A 36-foot tall tree with a canopy spread of 48 feet planted at the geographic center of the contiguous United States (Longitude=98°3'West; Latitude=39°0'North) tree would cast shadows at solar noon throughout the year as follows: August 21 North East September 21 North East October 21 North East January 21 North East December 21 North East November 21 North East February 21 North East March 21 North East April 21 North East July 21 North East June 21 North East May 21 North East