How can I see the green flash?

The sun is made up of lights that consist of primary and secondary colors, plus indigo. Together, these lights appear white - this is why the sun is pure white when it is high in the sky.

As the sun approaches the horizon (either sunrise or sunset) the shorter wavelengths (like blue) scatter and interact with air molecules (our atmosphere).

At this time, more green light than blue gets through the atmosphere and this helps explain why we can sometimes "catch" a green flash at sunset. In the sun's color spectrum (red, orange, yellow, green, blue, indigo and violet), green is the wavelength of maximum intensity, because of the sun's surface temperature.

So, in extremely clear air conditions, and more commonly over oceans where an object-free panorama exists, a green flash can be observed at the very instant the sun drops below the horizon. The horizon must not only be uncluttered by foreground objects but be pollution free as well. Usually, a spectator needs to be positioned at a distance of several miles from the horizon, almost to the point where the curvature of the Earth defines the limit.

Viewing the horizon looking west across the Chesapeake Bay is a natural setting to catch a green flash.