Is the beach at sunset the best place to observe a green flash and does the season matter?
The best place is where you have a Body of Water such as the Ocean or A lake. I have seen the Green Flash over Lake Erie as well as Delaware Bay. The Green Flash is caused by the Inversion Layer of Air when the Last tip of the sun hits it before setting. It is very brief so you need to know exactly what you are looking for. The sun will appear to turn Green for a few seconds. The best time to see this is in the summer because it is warmer and there is a thicker inversion layer. The Green Flash is caused by the same thing that causes Mirages.