Yesterday Isabel and I worked on a shade map of the Cambridge Community Center. We gathered data for three times of year: June, May (=late July) and August. For each time period and location, we recorded the times of day that the sun would hit it, using Jamie's cool Solar Pathfinder tool.
This is in preparation for putting in vegetable gardens.
The news was actually not so good - most of the area is shaded by a couple large trees and some smaller ones.
You can calculate the percent of total daily solar radiation based on numbers provided on the tool. In the picture, the red numbers are those percentages.
Here is June; click on it to see a version big enough to read the numbers:
There are just two "sweet spots": one in the northwest corner, just beyond the reach of the shadows from the tree and the building, and another between the two large trees along the western fence. Trees across the street on the south side, not shown on the map, get in the way of the sun in front of the building, on the south.
I also took the opportunity to measure the amount of sun at our house; we are very lucky to have ~80% sun in the pots out back, and probably near full sun in the roof containers. The porch pots get decent sun. The pots I put near the neighbors' roof water barrels get ~70%. Along the driveway gets only 25%-30%, and yet the cherry tomatoes did nicely there last year; maybe it would be a good place for lettuce and herbs in the summer when those plants don't mind some shade.