Crepuscular rays, in atmospheric optics, are rays of sunlight that appear to radiate from the point in the sky where the sun is located. These rays, which stream through gaps in clouds (particularly stratocumulus) or between other objects, are columns of sunlit air separated by darker cloud-shadowed regions. Despite seeming to converge at a point, the rays are in fact near-parallel shafts of sunlight, and their apparent convergence is a perspective effect.
Tonight, if you looked up to the sky, you would have seen anti-crepuscular rays. This is when the rays in some cases may extend across the sky and appear to converge at the antisolar point, the point on the sky sphere directly opposite the sun.
Tonight, the source for these anti-crepuscular rays were the distant thunderstorms in Minnesota and South Dakota.
— Zach Sharpe (@StormchaserZach) June 20, 2016