Hiding a script for roughly 12 hours at a time

I have a webcam on one of my sites looking out towards the ocean. so of course, there is roughly 12 hours when its dark there is nothing to see. I was considering hiding the window during this time and displaying a little message saying 'the camera is working, but its dark. the local time is … please bookmark us check back during daylight hours.

Im guessing I need to locate the server time, then make an offset to adjust to where I am. Also, the place I am working from doesn’t use daylight savings time so we are I think +6 GMT year round

Anyone ever done anything like this in the past?