The perfect sunbeam weather occurs on humid, hazy, summer mornings that follow an evening or nighttime of showers or thunderstorms. The air is filled with fog and haze particles which makes sunlight visible by diffraction, reflection, and scattering of the light. Shadows from trees or clouds provide the contrast needed to highlight the individual rays of light.
Sunbeams are really crepuscular rays that can occur any time of year. They originate from clouds, trees, buildings, or even windows. On the morning of June 17, the crepuscular rays shining through the trees near Oakton, Virginia were particularly vivid and well-defined. Thunderstorms occurred the previous evening which was followed by light ground fog in the morning that set the stage for the light show.
Read below for more photos of the sunbeams from June 17.