Factors to Consider When Assessing the Potential Effects of Shading

What is the most appropriate time of the year to evaluate the potential effects of shading?

General practice suggests that the most appropriate evaluation period is when there is minimal possible light available i.e. on the winter solstice when the sun’s path is at its lowest and shortest.  Most councils base district plan rules and guidelines on this period with the understanding of it being the worst case scenario.

Guidelines from the United Kingdom recommend the spring or autumn equinox as the most appropriate evaluation period.  This is due to the relative comparisons in the winter solstice being greatly influenced by the lower path in the sky of the sun and bad weather often preventing sunlight occurring during this time.

As yet, there is no clear research defining when is considered appropriate.  District plans may provide guidelines to assist with evaluating a project, but some other things to consider are:

  • How the space is used during the period of the year being assessed.
  • The climatic factors such as rain and cloud which affect the level of sunlight.
  • Surrounding seasonal factors i.e. deciduous trees.
  • The desire for shading to avoid overheating.

If you have any examples or thoughts on the topic, we would greatly appreciate the communication.  If you need assistance with a project, feel free to contact us at Sun Study Analysis.