The "Geeks" will love this...when does the sun go down?

[halds]

I think if you asking for a specific time, there is no answer. The sun begins to go down immediately after high noon, and ends is when the sun sets. Anything in between is a graded level of UV exposure.... you have to decide what you are happy to accommodate with you schedule. I just wait until after dinner, but I leave my pump run until we go to bed.